GHSA-9HF4-67FC-4VF4
Vulnerability from github – Published: 2024-09-20 14:40 – Updated: 2025-11-04 16:53Impact
Clients could clobber values set by intermediate proxies (such as X-Forwarded-For) by providing a underscore version of the same header (X-Forwarded_For). Any users trusting headers set by their proxy may be affected. Attackers may be able to downgrade connections to HTTP (non-SSL) or redirect responses, which could cause confidentiality leaks if combined with a separate MITM attack.
Patches
v6.4.3/v5.6.9 now discards any headers using underscores if the non-underscore version also exists. Effectively, allowing the proxy defined headers to always win.
Workarounds
Nginx has a underscores_in_headers configuration variable to discard these headers at the proxy level.
Any users that are implicitly trusting the proxy defined headers for security or availability should immediately cease doing so until upgraded to the fixed versions.
{
"affected": [
{
"package": {
"ecosystem": "RubyGems",
"name": "puma"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "5.6.9"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "RubyGems",
"name": "puma"
},
"ranges": [
{
"events": [
{
"introduced": "6.0.0"
},
{
"fixed": "6.4.3"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-45614"
],
"database_specific": {
"cwe_ids": [
"CWE-444",
"CWE-639"
],
"github_reviewed": true,
"github_reviewed_at": "2024-09-20T14:40:16Z",
"nvd_published_at": "2024-09-19T23:15:11Z",
"severity": "MODERATE"
},
"details": "### Impact\n\nClients could clobber values set by intermediate proxies (such as X-Forwarded-For) by providing a underscore version of the same header (X-Forwarded_For). Any users trusting headers set by their proxy may be affected. Attackers may be able to downgrade connections to HTTP (non-SSL) or redirect responses, which could cause confidentiality leaks if combined with a separate MITM attack. \n\n### Patches\nv6.4.3/v5.6.9 now discards any headers using underscores if the non-underscore version also exists. Effectively, allowing the proxy defined headers to always win.\n\n### Workarounds\nNginx has a [underscores_in_headers](https://nginx.org/en/docs/http/ngx_http_core_module.html#underscores_in_headers) configuration variable to discard these headers at the proxy level.\n\nAny users that are implicitly trusting the proxy defined headers for security or availability should immediately cease doing so until upgraded to the fixed versions.",
"id": "GHSA-9hf4-67fc-4vf4",
"modified": "2025-11-04T16:53:06Z",
"published": "2024-09-20T14:40:16Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/puma/puma/security/advisories/GHSA-9hf4-67fc-4vf4"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-45614"
},
{
"type": "WEB",
"url": "https://github.com/puma/puma/commit/cac3fd18cf29ed43719ff5d52d9cfec215f0a043"
},
{
"type": "WEB",
"url": "https://github.com/puma/puma/commit/f196b23be24712fb8fb16051cc124798cc84f70e"
},
{
"type": "PACKAGE",
"url": "https://github.com/puma/puma"
},
{
"type": "WEB",
"url": "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/puma/CVE-2024-45614.yml"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2024/11/msg00004.html"
},
{
"type": "WEB",
"url": "https://nginx.org/en/docs/http/ngx_http_core_module.html#underscores_in_headers"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Puma\u0027s header normalization allows for client to clobber proxy set headers"
}
Sightings
| Author | Source | Type | Date |
|---|
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.