Action not permitted
Modal body text goes here.
Modal Title
Modal Body
PYSEC-2019-137
Vulnerability from pysec - Published: 2019-12-20 23:15 - Updated: 2020-02-25 17:15
VLAI
Details
Waitress through version 1.3.1 would parse the Transfer-Encoding header and only look for a single string value, if that value was not chunked it would fall through and use the Content-Length header instead. According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with chunked. Requests sent with: "Transfer-Encoding: gzip, chunked" would incorrectly get ignored, and the request would use a Content-Length header instead to determine the body size of the HTTP message. This could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining. This issue is fixed in Waitress 1.4.0.
Impacted products
| Name | purl | waitress | pkg:pypi/waitress |
|---|
Aliases
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "waitress",
"purl": "pkg:pypi/waitress"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "f11093a6b3240fc26830b6111e826128af7771c3"
}
],
"repo": "https://github.com/Pylons/waitress",
"type": "GIT"
},
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.3.1"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"0.1",
"0.2",
"0.3",
"0.4",
"0.5",
"0.6",
"0.6.1",
"0.7",
"0.8",
"0.8.1",
"0.8.2",
"0.8.3",
"0.8.4",
"0.8.5",
"0.8.6",
"0.8.7",
"0.8.8",
"0.8.9",
"0.8.10",
"0.8.11b0",
"0.9.0b0",
"0.9.0b1",
"0.9.0",
"1.0a1",
"1.0a2",
"1.0.0",
"1.0.1",
"1.0.2",
"1.1.0",
"1.2.0b1",
"1.2.0b2",
"1.2.0b3",
"1.2.0",
"1.2.1",
"1.3.0b0",
"1.3.0"
]
}
],
"aliases": [
"CVE-2019-16786",
"GHSA-g2xc-35jw-c63p"
],
"details": "Waitress through version 1.3.1 would parse the Transfer-Encoding header and only look for a single string value, if that value was not chunked it would fall through and use the Content-Length header instead. According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with chunked. Requests sent with: \"Transfer-Encoding: gzip, chunked\" would incorrectly get ignored, and the request would use a Content-Length header instead to determine the body size of the HTTP message. This could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining. This issue is fixed in Waitress 1.4.0.",
"id": "PYSEC-2019-137",
"modified": "2020-02-25T17:15:00Z",
"published": "2019-12-20T23:15:00Z",
"references": [
{
"type": "ADVISORY",
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-g2xc-35jw-c63p"
},
{
"type": "FIX",
"url": "https://github.com/Pylons/waitress/commit/f11093a6b3240fc26830b6111e826128af7771c3"
},
{
"type": "WEB",
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GVDHR2DNKCNQ7YQXISJ45NT4IQDX3LJ7/"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LYEOTGWJZVKPRXX2HBNVIYWCX73QYPM5/"
},
{
"type": "ADVISORY",
"url": "https://access.redhat.com/errata/RHSA-2020:0720"
}
]
}
BREW-BACKGROUNDREMOVER-C… (GHSA-G2XC-35JW-C63P)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:37 – Updated: 2026-09-09 23:43 – Source website
VLAI
Summary
HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress
Details
Impact
Waitress would parse the Transfer-Encoding header and only look for a single string value, if that value was not chunked it would fall through and use the Content-Length header instead.
According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with chunked.
Requests sent with:
Transfer-Encoding: gzip, chunked
Would incorrectly get ignored, and the request would use a Content-Length header instead to determine the body size of the HTTP message.
This could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining.
Patches
This issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies.
Waitress will now return a 501 Not Implemented error if the Transfer-Encoding is not chunked or contains multiple elements. Waitress does not support any transfer codings such as gzip or deflate.
The Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don't cause any changes in behavior.
Workarounds
Various reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn't use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).
Issues/more security issues:
- open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)
- email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)
Severity
References
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "waitress",
"resource_purl": "pkg:pypi/waitress@3.0.2",
"upstream_fixed_in": "1.4.0"
},
"package": {
"ecosystem": "Homebrew",
"name": "backgroundremover",
"purl": "pkg:brew/backgroundremover"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.4.5"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/waitress@3.0.2",
"name": "waitress",
"resource": "waitress",
"strategy": "registry",
"subject_version": "3.0.2"
}
]
},
"details": "### Impact\n\nWaitress would parse the `Transfer-Encoding` header and only look for a single string value, if that value was not `chunked` it would fall through and use the `Content-Length` header instead.\n\nAccording to the HTTP standard `Transfer-Encoding` should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with `chunked`.\n\nRequests sent with:\n\n```\nTransfer-Encoding: gzip, chunked\n```\n\nWould incorrectly get ignored, and the request would use a `Content-Length` header instead to determine the body size of the HTTP message.\n\nThis could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining.\n\n### Patches\n\nThis issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies. \n\nWaitress will now return a 501 Not Implemented error if the `Transfer-Encoding` is not `chunked` or contains multiple elements. Waitress does not support any transfer codings such as `gzip` or `deflate`.\n\nThe Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don\u0026#39;t cause any changes in behavior.\n\n### Workarounds\n\nVarious reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn\u0026#39;t use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).\n\n### Issues/more security issues:\n\n* open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)\n* email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)",
"id": "BREW-backgroundremover-CVE-2019-16786",
"modified": "2026-09-09T23:43:06Z",
"published": "2026-08-13T16:37:03Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-g2xc-35jw-c63p"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-16786"
},
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/commit/f11093a6b3240fc26830b6111e826128af7771c3"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2020:0720"
},
{
"type": "WEB",
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"type": "PACKAGE",
"url": "https://github.com/Pylons/waitress"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/waitress/PYSEC-2019-137.yaml"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GVDHR2DNKCNQ7YQXISJ45NT4IQDX3LJ7"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LYEOTGWJZVKPRXX2HBNVIYWCX73QYPM5"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress",
"upstream": [
"GHSA-g2xc-35jw-c63p",
"CVE-2019-16786",
"PYSEC-2019-137"
]
}
BREW-ICLOUDPD-CVE-2019-16786 (GHSA-G2XC-35JW-C63P)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:59 – Updated: 2026-09-10 00:11 – Source website
VLAI
Summary
HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress
Details
Impact
Waitress would parse the Transfer-Encoding header and only look for a single string value, if that value was not chunked it would fall through and use the Content-Length header instead.
According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with chunked.
Requests sent with:
Transfer-Encoding: gzip, chunked
Would incorrectly get ignored, and the request would use a Content-Length header instead to determine the body size of the HTTP message.
This could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining.
Patches
This issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies.
Waitress will now return a 501 Not Implemented error if the Transfer-Encoding is not chunked or contains multiple elements. Waitress does not support any transfer codings such as gzip or deflate.
The Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don't cause any changes in behavior.
Workarounds
Various reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn't use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).
Issues/more security issues:
- open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)
- email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)
Severity
References
| URL | Type | ||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||||||||||||||||||||||
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "waitress",
"resource_purl": "pkg:pypi/waitress@3.0.2",
"upstream_fixed_in": "1.4.0"
},
"package": {
"ecosystem": "Homebrew",
"name": "icloudpd",
"purl": "pkg:brew/icloudpd"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.32.3"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/waitress@3.0.2",
"name": "waitress",
"resource": "waitress",
"strategy": "registry",
"subject_version": "3.0.2"
}
]
},
"details": "### Impact\n\nWaitress would parse the `Transfer-Encoding` header and only look for a single string value, if that value was not `chunked` it would fall through and use the `Content-Length` header instead.\n\nAccording to the HTTP standard `Transfer-Encoding` should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with `chunked`.\n\nRequests sent with:\n\n```\nTransfer-Encoding: gzip, chunked\n```\n\nWould incorrectly get ignored, and the request would use a `Content-Length` header instead to determine the body size of the HTTP message.\n\nThis could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining.\n\n### Patches\n\nThis issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies. \n\nWaitress will now return a 501 Not Implemented error if the `Transfer-Encoding` is not `chunked` or contains multiple elements. Waitress does not support any transfer codings such as `gzip` or `deflate`.\n\nThe Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don\u0026#39;t cause any changes in behavior.\n\n### Workarounds\n\nVarious reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn\u0026#39;t use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).\n\n### Issues/more security issues:\n\n* open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)\n* email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)",
"id": "BREW-icloudpd-CVE-2019-16786",
"modified": "2026-09-10T00:11:17Z",
"published": "2026-08-13T16:59:03Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-g2xc-35jw-c63p"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-16786"
},
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/commit/f11093a6b3240fc26830b6111e826128af7771c3"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2020:0720"
},
{
"type": "WEB",
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"type": "PACKAGE",
"url": "https://github.com/Pylons/waitress"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/waitress/PYSEC-2019-137.yaml"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GVDHR2DNKCNQ7YQXISJ45NT4IQDX3LJ7"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LYEOTGWJZVKPRXX2HBNVIYWCX73QYPM5"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress",
"upstream": [
"GHSA-g2xc-35jw-c63p",
"CVE-2019-16786",
"PYSEC-2019-137"
]
}
BREW-MKTXP-CVE-2019-16786 (GHSA-G2XC-35JW-C63P)
Vulnerability from osv_homebrew – Published: 2026-08-13 17:14 – Updated: 2026-09-10 00:32 – Source website
VLAI
Summary
HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress
Details
Impact
Waitress would parse the Transfer-Encoding header and only look for a single string value, if that value was not chunked it would fall through and use the Content-Length header instead.
According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with chunked.
Requests sent with:
Transfer-Encoding: gzip, chunked
Would incorrectly get ignored, and the request would use a Content-Length header instead to determine the body size of the HTTP message.
This could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining.
Patches
This issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies.
Waitress will now return a 501 Not Implemented error if the Transfer-Encoding is not chunked or contains multiple elements. Waitress does not support any transfer codings such as gzip or deflate.
The Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don't cause any changes in behavior.
Workarounds
Various reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn't use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).
Issues/more security issues:
- open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)
- email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)
Severity
References
| URL | Type | ||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||||||||||||||||||||||
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "waitress",
"resource_purl": "pkg:pypi/waitress@3.0.2",
"upstream_fixed_in": "1.4.0"
},
"package": {
"ecosystem": "Homebrew",
"name": "mktxp",
"purl": "pkg:brew/mktxp"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.2.19"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/waitress@3.0.2",
"name": "waitress",
"resource": "waitress",
"strategy": "registry",
"subject_version": "3.0.2"
}
]
},
"details": "### Impact\n\nWaitress would parse the `Transfer-Encoding` header and only look for a single string value, if that value was not `chunked` it would fall through and use the `Content-Length` header instead.\n\nAccording to the HTTP standard `Transfer-Encoding` should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with `chunked`.\n\nRequests sent with:\n\n```\nTransfer-Encoding: gzip, chunked\n```\n\nWould incorrectly get ignored, and the request would use a `Content-Length` header instead to determine the body size of the HTTP message.\n\nThis could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining.\n\n### Patches\n\nThis issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies. \n\nWaitress will now return a 501 Not Implemented error if the `Transfer-Encoding` is not `chunked` or contains multiple elements. Waitress does not support any transfer codings such as `gzip` or `deflate`.\n\nThe Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don\u0026#39;t cause any changes in behavior.\n\n### Workarounds\n\nVarious reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn\u0026#39;t use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).\n\n### Issues/more security issues:\n\n* open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)\n* email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)",
"id": "BREW-mktxp-CVE-2019-16786",
"modified": "2026-09-10T00:32:14Z",
"published": "2026-08-13T17:14:17Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-g2xc-35jw-c63p"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-16786"
},
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/commit/f11093a6b3240fc26830b6111e826128af7771c3"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2020:0720"
},
{
"type": "WEB",
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"type": "PACKAGE",
"url": "https://github.com/Pylons/waitress"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/waitress/PYSEC-2019-137.yaml"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GVDHR2DNKCNQ7YQXISJ45NT4IQDX3LJ7"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LYEOTGWJZVKPRXX2HBNVIYWCX73QYPM5"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress",
"upstream": [
"GHSA-g2xc-35jw-c63p",
"CVE-2019-16786",
"PYSEC-2019-137"
]
}
CVE-2019-16786 (GCVE-0-2019-16786)
Vulnerability from cvelistv5 – Published: 2019-12-20 23:00 – Updated: 2024-08-05 01:24
VLAI
EPSS
VEX
Title
HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress
Summary
Waitress through version 1.3.1 would parse the Transfer-Encoding header and only look for a single string value, if that value was not chunked it would fall through and use the Content-Length header instead. According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with chunked. Requests sent with: "Transfer-Encoding: gzip, chunked" would incorrectly get ignored, and the request would use a Content-Length header instead to determine the body size of the HTTP message. This could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining. This issue is fixed in Waitress 1.4.0.
Severity
7.1 (High)
CWE
- CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')
Assigner
References
8 references
| URL | Tags |
|---|---|
| https://lists.fedoraproject.org/archives/list/pac… | vendor-advisoryx_refsource_FEDORA |
| https://lists.fedoraproject.org/archives/list/pac… | vendor-advisoryx_refsource_FEDORA |
| https://access.redhat.com/errata/RHSA-2020:0720 | vendor-advisoryx_refsource_REDHAT |
| https://www.oracle.com/security-alerts/cpuapr2022.html | x_refsource_MISC |
| https://docs.pylonsproject.org/projects/waitress/… | x_refsource_MISC |
| https://github.com/Pylons/waitress/security/advis… | x_refsource_CONFIRM |
| https://github.com/Pylons/waitress/commit/f11093a… | x_refsource_MISC |
| https://lists.debian.org/debian-lts-announce/2022… | mailing-listx_refsource_MLIST |
Impacted products
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-05T01:24:48.017Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"name": "FEDORA-2020-bdcc8ffc24",
"tags": [
"vendor-advisory",
"x_refsource_FEDORA",
"x_transferred"
],
"url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GVDHR2DNKCNQ7YQXISJ45NT4IQDX3LJ7/"
},
{
"name": "FEDORA-2020-65a7744e38",
"tags": [
"vendor-advisory",
"x_refsource_FEDORA",
"x_transferred"
],
"url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LYEOTGWJZVKPRXX2HBNVIYWCX73QYPM5/"
},
{
"name": "RHSA-2020:0720",
"tags": [
"vendor-advisory",
"x_refsource_REDHAT",
"x_transferred"
],
"url": "https://access.redhat.com/errata/RHSA-2020:0720"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"tags": [
"x_refsource_CONFIRM",
"x_transferred"
],
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-g2xc-35jw-c63p"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://github.com/Pylons/waitress/commit/f11093a6b3240fc26830b6111e826128af7771c3"
},
{
"name": "[debian-lts-announce] 20220512 [SECURITY] [DLA 3000-1] waitress security update",
"tags": [
"mailing-list",
"x_refsource_MLIST",
"x_transferred"
],
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
}
],
"title": "CVE Program Container"
}
],
"cna": {
"affected": [
{
"product": "Waitress",
"vendor": "Pylons",
"versions": [
{
"lessThanOrEqual": "1.3.1",
"status": "affected",
"version": "\u003c= 1.3.1",
"versionType": "custom"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Waitress through version 1.3.1 would parse the Transfer-Encoding header and only look for a single string value, if that value was not chunked it would fall through and use the Content-Length header instead. According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with chunked. Requests sent with: \"Transfer-Encoding: gzip, chunked\" would incorrectly get ignored, and the request would use a Content-Length header instead to determine the body size of the HTTP message. This could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining. This issue is fixed in Waitress 1.4.0."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 7.1,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "LOW",
"privilegesRequired": "LOW",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-444",
"description": "CWE-444 Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request Smuggling\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2022-05-12T23:06:10.000Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "FEDORA-2020-bdcc8ffc24",
"tags": [
"vendor-advisory",
"x_refsource_FEDORA"
],
"url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GVDHR2DNKCNQ7YQXISJ45NT4IQDX3LJ7/"
},
{
"name": "FEDORA-2020-65a7744e38",
"tags": [
"vendor-advisory",
"x_refsource_FEDORA"
],
"url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LYEOTGWJZVKPRXX2HBNVIYWCX73QYPM5/"
},
{
"name": "RHSA-2020:0720",
"tags": [
"vendor-advisory",
"x_refsource_REDHAT"
],
"url": "https://access.redhat.com/errata/RHSA-2020:0720"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-g2xc-35jw-c63p"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/Pylons/waitress/commit/f11093a6b3240fc26830b6111e826128af7771c3"
},
{
"name": "[debian-lts-announce] 20220512 [SECURITY] [DLA 3000-1] waitress security update",
"tags": [
"mailing-list",
"x_refsource_MLIST"
],
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
}
],
"source": {
"advisory": "GHSA-g2xc-35jw-c63p",
"discovery": "UNKNOWN"
},
"title": "HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress",
"x_legacyV4Record": {
"CVE_data_meta": {
"ASSIGNER": "security-advisories@github.com",
"ID": "CVE-2019-16786",
"STATE": "PUBLIC",
"TITLE": "HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress"
},
"affects": {
"vendor": {
"vendor_data": [
{
"product": {
"product_data": [
{
"product_name": "Waitress",
"version": {
"version_data": [
{
"version_affected": "\u003c=",
"version_name": "\u003c= 1.3.1",
"version_value": "1.3.1"
}
]
}
}
]
},
"vendor_name": "Pylons"
}
]
}
},
"data_format": "MITRE",
"data_type": "CVE",
"data_version": "4.0",
"description": {
"description_data": [
{
"lang": "eng",
"value": "Waitress through version 1.3.1 would parse the Transfer-Encoding header and only look for a single string value, if that value was not chunked it would fall through and use the Content-Length header instead. According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with chunked. Requests sent with: \"Transfer-Encoding: gzip, chunked\" would incorrectly get ignored, and the request would use a Content-Length header instead to determine the body size of the HTTP message. This could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining. This issue is fixed in Waitress 1.4.0."
}
]
},
"impact": {
"cvss": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 7.1,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "LOW",
"privilegesRequired": "LOW",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N",
"version": "3.1"
}
},
"problemtype": {
"problemtype_data": [
{
"description": [
{
"lang": "eng",
"value": "CWE-444 Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request Smuggling\u0027)"
}
]
}
]
},
"references": {
"reference_data": [
{
"name": "FEDORA-2020-bdcc8ffc24",
"refsource": "FEDORA",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GVDHR2DNKCNQ7YQXISJ45NT4IQDX3LJ7/"
},
{
"name": "FEDORA-2020-65a7744e38",
"refsource": "FEDORA",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LYEOTGWJZVKPRXX2HBNVIYWCX73QYPM5/"
},
{
"name": "RHSA-2020:0720",
"refsource": "REDHAT",
"url": "https://access.redhat.com/errata/RHSA-2020:0720"
},
{
"name": "https://www.oracle.com/security-alerts/cpuapr2022.html",
"refsource": "MISC",
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
},
{
"name": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes",
"refsource": "MISC",
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"name": "https://github.com/Pylons/waitress/security/advisories/GHSA-g2xc-35jw-c63p",
"refsource": "CONFIRM",
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-g2xc-35jw-c63p"
},
{
"name": "https://github.com/Pylons/waitress/commit/f11093a6b3240fc26830b6111e826128af7771c3",
"refsource": "MISC",
"url": "https://github.com/Pylons/waitress/commit/f11093a6b3240fc26830b6111e826128af7771c3"
},
{
"name": "[debian-lts-announce] 20220512 [SECURITY] [DLA 3000-1] waitress security update",
"refsource": "MLIST",
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
}
]
},
"source": {
"advisory": "GHSA-g2xc-35jw-c63p",
"discovery": "UNKNOWN"
}
}
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2019-16786",
"datePublished": "2019-12-20T23:00:20.000Z",
"dateReserved": "2019-09-24T00:00:00.000Z",
"dateUpdated": "2024-08-05T01:24:48.017Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1"
}
GHSA-G2XC-35JW-C63P
Vulnerability from github – Published: 2019-12-20 23:04 – Updated: 2024-11-19 13:57
VLAI
Summary
HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress
Details
Impact
Waitress would parse the Transfer-Encoding header and only look for a single string value, if that value was not chunked it would fall through and use the Content-Length header instead.
According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with chunked.
Requests sent with:
Transfer-Encoding: gzip, chunked
Would incorrectly get ignored, and the request would use a Content-Length header instead to determine the body size of the HTTP message.
This could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining.
Patches
This issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies.
Waitress will now return a 501 Not Implemented error if the Transfer-Encoding is not chunked or contains multiple elements. Waitress does not support any transfer codings such as gzip or deflate.
The Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don't cause any changes in behavior.
Workarounds
Various reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn't use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).
Issues/more security issues:
- open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)
- email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)
Severity
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "waitress"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.4.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2019-16786"
],
"database_specific": {
"cwe_ids": [
"CWE-444"
],
"github_reviewed": true,
"github_reviewed_at": "2019-12-20T23:01:53Z",
"nvd_published_at": "2019-12-20T23:15:00Z",
"severity": "MODERATE"
},
"details": "### Impact\n\nWaitress would parse the `Transfer-Encoding` header and only look for a single string value, if that value was not `chunked` it would fall through and use the `Content-Length` header instead.\n\nAccording to the HTTP standard `Transfer-Encoding` should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with `chunked`.\n\nRequests sent with:\n\n```\nTransfer-Encoding: gzip, chunked\n```\n\nWould incorrectly get ignored, and the request would use a `Content-Length` header instead to determine the body size of the HTTP message.\n\nThis could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining.\n\n### Patches\n\nThis issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies. \n\nWaitress will now return a 501 Not Implemented error if the `Transfer-Encoding` is not `chunked` or contains multiple elements. Waitress does not support any transfer codings such as `gzip` or `deflate`.\n\nThe Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don\u0026#39;t cause any changes in behavior.\n\n### Workarounds\n\nVarious reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn\u0026#39;t use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).\n\n### Issues/more security issues:\n\n* open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)\n* email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)",
"id": "GHSA-g2xc-35jw-c63p",
"modified": "2024-11-19T13:57:29Z",
"published": "2019-12-20T23:04:18Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-g2xc-35jw-c63p"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-16786"
},
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/commit/f11093a6b3240fc26830b6111e826128af7771c3"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2020:0720"
},
{
"type": "WEB",
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"type": "PACKAGE",
"url": "https://github.com/Pylons/waitress"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/waitress/PYSEC-2019-137.yaml"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GVDHR2DNKCNQ7YQXISJ45NT4IQDX3LJ7"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LYEOTGWJZVKPRXX2HBNVIYWCX73QYPM5"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "HTTP Request Smuggling: Invalid Transfer-Encoding in Waitress"
}
Loading…
Trend slope:
-
(linear fit over daily sighting counts)
Show additional events:
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
Loading…
Loading…