Vulnerability-Lookup

CVE-2026-73494 (GCVE-0-2026-73494)

Vulnerability from cvelistv5 – Published: 2026-09-14 17:33 – Updated: 2026-09-14 20:05

Title

blaze: Multiple HTTP/1.1 request-smuggling primitives in blaze's Java wire parser

Summary

blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and from 1.0.0-M1 until 1.0.0-M42, five HTTP/1.1 conformance laxities in the hand-written Java parser under http/src/main/java/org/http4s/blaze/http/parser/ can cause blaze to derive a different request boundary than a stricter fronting intermediary. A default BlazeServerBuilder accepts invalid or valueless header field names that violate tchar syntax, obsolete folded field lines (obs-fold), unsupported Transfer-Encoding values, duplicate Content-Length fields, and requests containing both Transfer-Encoding and Content-Length. If a lenient or legacy proxy forwards the malformed bytes but interprets them differently, the disagreement can permit front-end authorization bypass, response-queue poisoning on pooled backend connections, or cache poisoning. Exploitation requires a pair of disagreeing parsers; no non-default blaze configuration is required. The affected checks are enforced in BodyAndHeaderParser and Http1ServerParser. This issue is fixed in versions 0.23.18 and 1.0.0-M42.

Severity

7.4 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-14 19:21 UTC

CWE

CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Assigner

GitHub_M mitre root

References

9 references

URL	Tags
https://github.com/http4s/blaze/security/advisori…	x_refsource_CONFIRM
https://github.com/http4s/blaze/commit/3f7c022e30…	x_refsource_MISC
https://github.com/http4s/blaze/commit/4eec200780…	x_refsource_MISC
https://github.com/http4s/blaze/commit/927b67753a…	x_refsource_MISC
https://github.com/http4s/blaze/commit/a54bc9cd31…	x_refsource_MISC
https://github.com/http4s/blaze/commit/c47d9675f8…	x_refsource_MISC
https://github.com/http4s/blaze/commit/e871ebb1d2…	x_refsource_MISC
https://github.com/http4s/blaze/releases/tag/v0.23.18	x_refsource_MISC
https://github.com/http4s/blaze/releases/tag/v1.0.0-M42	x_refsource_MISC

Impacted products

4 products

Vendor	Product	Version	CPE status
http4s	blaze	Affected: < 0.23.18 Affected: >= 1.0.0-M1, < 1.0.0-M42	guessed
org.http4s	blaze-http_2.13	Affected: < 0.23.18 Affected: >= 1.0.0-M1, < 1.0.0-M42	guessed
org.http4s	blaze-http_3	Affected: < 0.23.18 Affected: >= 1.0.0-M1, < 1.0.0-M42	guessed
org.http4s	http4s-blaze-server_2.13	Affected: < 0.23.18	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-73494",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-14T19:21:20.842876Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-14T20:05:52.181Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "blaze",
          "vendor": "http4s",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.23.18"
            },
            {
              "status": "affected",
              "version": "\u003e= 1.0.0-M1, \u003c 1.0.0-M42"
            }
          ]
        },
        {
          "product": "blaze-http_2.13",
          "vendor": "org.http4s",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.23.18"
            },
            {
              "status": "affected",
              "version": "\u003e= 1.0.0-M1, \u003c 1.0.0-M42"
            }
          ]
        },
        {
          "product": "blaze-http_3",
          "vendor": "org.http4s",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.23.18"
            },
            {
              "status": "affected",
              "version": "\u003e= 1.0.0-M1, \u003c 1.0.0-M42"
            }
          ]
        },
        {
          "product": "http4s-blaze-server_2.13",
          "vendor": "org.http4s",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.23.18"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and from 1.0.0-M1 until 1.0.0-M42, five HTTP/1.1 conformance laxities in the hand-written Java parser under http/src/main/java/org/http4s/blaze/http/parser/ can cause blaze to derive a different request boundary than a stricter fronting intermediary. A default BlazeServerBuilder accepts invalid or valueless header field names that violate tchar syntax, obsolete folded field lines (obs-fold), unsupported Transfer-Encoding values, duplicate Content-Length fields, and requests containing both Transfer-Encoding and Content-Length. If a lenient or legacy proxy forwards the malformed bytes but interprets them differently, the disagreement can permit front-end authorization bypass, response-queue poisoning on pooled backend connections, or cache poisoning. Exploitation requires a pair of disagreeing parsers; no non-default blaze configuration is required. The affected checks are enforced in BodyAndHeaderParser and Http1ServerParser. This issue is fixed in versions 0.23.18 and 1.0.0-M42."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.4,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-444",
              "description": "CWE-444: Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-14T17:33:49.671Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/http4s/blaze/security/advisories/GHSA-mhvj-jhpq-885v",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/http4s/blaze/security/advisories/GHSA-mhvj-jhpq-885v"
        },
        {
          "name": "https://github.com/http4s/blaze/commit/3f7c022e306631b006dcb43a1d7f65c0d1966f17",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/http4s/blaze/commit/3f7c022e306631b006dcb43a1d7f65c0d1966f17"
        },
        {
          "name": "https://github.com/http4s/blaze/commit/4eec2007806aa9acfefb00ebb636ddc39a147a96",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/http4s/blaze/commit/4eec2007806aa9acfefb00ebb636ddc39a147a96"
        },
        {
          "name": "https://github.com/http4s/blaze/commit/927b67753a78c13c4445dac9307f511f5c4878c3",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/http4s/blaze/commit/927b67753a78c13c4445dac9307f511f5c4878c3"
        },
        {
          "name": "https://github.com/http4s/blaze/commit/a54bc9cd31758335c7f24e29763622fd03fcf734",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/http4s/blaze/commit/a54bc9cd31758335c7f24e29763622fd03fcf734"
        },
        {
          "name": "https://github.com/http4s/blaze/commit/c47d9675f87603f11b32a11d503626bdf9be5c7a",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/http4s/blaze/commit/c47d9675f87603f11b32a11d503626bdf9be5c7a"
        },
        {
          "name": "https://github.com/http4s/blaze/commit/e871ebb1d27f50c98fd56988526ce42d0fee74d6",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/http4s/blaze/commit/e871ebb1d27f50c98fd56988526ce42d0fee74d6"
        },
        {
          "name": "https://github.com/http4s/blaze/releases/tag/v0.23.18",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/http4s/blaze/releases/tag/v0.23.18"
        },
        {
          "name": "https://github.com/http4s/blaze/releases/tag/v1.0.0-M42",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/http4s/blaze/releases/tag/v1.0.0-M42"
        }
      ],
      "source": {
        "advisory": "GHSA-mhvj-jhpq-885v",
        "discovery": "UNKNOWN"
      },
      "title": "blaze: Multiple HTTP/1.1 request-smuggling primitives in blaze\u0027s Java wire parser"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-73494",
    "datePublished": "2026-09-14T17:33:49.671Z",
    "dateReserved": "2026-08-12T19:00:33.735Z",
    "dateUpdated": "2026-09-14T20:05:52.181Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-73494",
      "date": "2026-09-17",
      "epss": "0.00374",
      "percentile": "0.31149"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-73494\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-09-14T18:19:58.857\",\"lastModified\":\"2026-09-14T20:16:50.707\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and from 1.0.0-M1 until 1.0.0-M42, five HTTP/1.1 conformance laxities in the hand-written Java parser under http/src/main/java/org/http4s/blaze/http/parser/ can cause blaze to derive a different request boundary than a stricter fronting intermediary. A default BlazeServerBuilder accepts invalid or valueless header field names that violate tchar syntax, obsolete folded field lines (obs-fold), unsupported Transfer-Encoding values, duplicate Content-Length fields, and requests containing both Transfer-Encoding and Content-Length. If a lenient or legacy proxy forwards the malformed bytes but interprets them differently, the disagreement can permit front-end authorization bypass, response-queue poisoning on pooled backend connections, or cache poisoning. Exploitation requires a pair of disagreeing parsers; no non-default blaze configuration is required. The affected checks are enforced in BodyAndHeaderParser and Http1ServerParser. This issue is fixed in versions 0.23.18 and 1.0.0-M42.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"http4s\",\"product\":\"blaze\",\"versions\":[{\"version\":\"\u003c 0.23.18\",\"status\":\"affected\"},{\"version\":\"\u003e= 1.0.0-M1, \u003c 1.0.0-M42\",\"status\":\"affected\"}]},{\"vendor\":\"org.http4s\",\"product\":\"blaze-http_2.13\",\"versions\":[{\"version\":\"\u003c 0.23.18\",\"status\":\"affected\"},{\"version\":\"\u003e= 1.0.0-M1, \u003c 1.0.0-M42\",\"status\":\"affected\"}]},{\"vendor\":\"org.http4s\",\"product\":\"blaze-http_3\",\"versions\":[{\"version\":\"\u003c 0.23.18\",\"status\":\"affected\"},{\"version\":\"\u003e= 1.0.0-M1, \u003c 1.0.0-M42\",\"status\":\"affected\"}]},{\"vendor\":\"org.http4s\",\"product\":\"http4s-blaze-server_2.13\",\"versions\":[{\"version\":\"\u003c 0.23.18\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N\",\"baseScore\":7.4,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.2,\"impactScore\":5.2}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-09-14T19:21:20.842876Z\",\"id\":\"CVE-2026-73494\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"total\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-444\"}]}],\"references\":[{\"url\":\"https://github.com/http4s/blaze/commit/3f7c022e306631b006dcb43a1d7f65c0d1966f17\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/http4s/blaze/commit/4eec2007806aa9acfefb00ebb636ddc39a147a96\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/http4s/blaze/commit/927b67753a78c13c4445dac9307f511f5c4878c3\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/http4s/blaze/commit/a54bc9cd31758335c7f24e29763622fd03fcf734\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/http4s/blaze/commit/c47d9675f87603f11b32a11d503626bdf9be5c7a\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/http4s/blaze/commit/e871ebb1d27f50c98fd56988526ce42d0fee74d6\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/http4s/blaze/releases/tag/v0.23.18\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/http4s/blaze/releases/tag/v1.0.0-M42\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/http4s/blaze/security/advisories/GHSA-mhvj-jhpq-885v\",\"source\":\"security-advisories@github.com\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-73494\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-09-14T19:21:20.842876Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-09-14T19:21:22.363Z\"}}], \"cna\": {\"title\": \"blaze: Multiple HTTP/1.1 request-smuggling primitives in blaze\u0027s Java wire parser\", \"source\": {\"advisory\": \"GHSA-mhvj-jhpq-885v\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.4, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"HIGH\"}}], \"affected\": [{\"vendor\": \"http4s\", \"product\": \"blaze\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 0.23.18\"}, {\"status\": \"affected\", \"version\": \"\u003e= 1.0.0-M1, \u003c 1.0.0-M42\"}]}, {\"vendor\": \"org.http4s\", \"product\": \"blaze-http_2.13\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 0.23.18\"}, {\"status\": \"affected\", \"version\": \"\u003e= 1.0.0-M1, \u003c 1.0.0-M42\"}]}, {\"vendor\": \"org.http4s\", \"product\": \"blaze-http_3\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 0.23.18\"}, {\"status\": \"affected\", \"version\": \"\u003e= 1.0.0-M1, \u003c 1.0.0-M42\"}]}, {\"vendor\": \"org.http4s\", \"product\": \"http4s-blaze-server_2.13\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 0.23.18\"}]}], \"references\": [{\"url\": \"https://github.com/http4s/blaze/security/advisories/GHSA-mhvj-jhpq-885v\", \"name\": \"https://github.com/http4s/blaze/security/advisories/GHSA-mhvj-jhpq-885v\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://github.com/http4s/blaze/commit/3f7c022e306631b006dcb43a1d7f65c0d1966f17\", \"name\": \"https://github.com/http4s/blaze/commit/3f7c022e306631b006dcb43a1d7f65c0d1966f17\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/http4s/blaze/commit/4eec2007806aa9acfefb00ebb636ddc39a147a96\", \"name\": \"https://github.com/http4s/blaze/commit/4eec2007806aa9acfefb00ebb636ddc39a147a96\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/http4s/blaze/commit/927b67753a78c13c4445dac9307f511f5c4878c3\", \"name\": \"https://github.com/http4s/blaze/commit/927b67753a78c13c4445dac9307f511f5c4878c3\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/http4s/blaze/commit/a54bc9cd31758335c7f24e29763622fd03fcf734\", \"name\": \"https://github.com/http4s/blaze/commit/a54bc9cd31758335c7f24e29763622fd03fcf734\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/http4s/blaze/commit/c47d9675f87603f11b32a11d503626bdf9be5c7a\", \"name\": \"https://github.com/http4s/blaze/commit/c47d9675f87603f11b32a11d503626bdf9be5c7a\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/http4s/blaze/commit/e871ebb1d27f50c98fd56988526ce42d0fee74d6\", \"name\": \"https://github.com/http4s/blaze/commit/e871ebb1d27f50c98fd56988526ce42d0fee74d6\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/http4s/blaze/releases/tag/v0.23.18\", \"name\": \"https://github.com/http4s/blaze/releases/tag/v0.23.18\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/http4s/blaze/releases/tag/v1.0.0-M42\", \"name\": \"https://github.com/http4s/blaze/releases/tag/v1.0.0-M42\", \"tags\": [\"x_refsource_MISC\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and from 1.0.0-M1 until 1.0.0-M42, five HTTP/1.1 conformance laxities in the hand-written Java parser under http/src/main/java/org/http4s/blaze/http/parser/ can cause blaze to derive a different request boundary than a stricter fronting intermediary. A default BlazeServerBuilder accepts invalid or valueless header field names that violate tchar syntax, obsolete folded field lines (obs-fold), unsupported Transfer-Encoding values, duplicate Content-Length fields, and requests containing both Transfer-Encoding and Content-Length. If a lenient or legacy proxy forwards the malformed bytes but interprets them differently, the disagreement can permit front-end authorization bypass, response-queue poisoning on pooled backend connections, or cache poisoning. Exploitation requires a pair of disagreeing parsers; no non-default blaze configuration is required. The affected checks are enforced in BodyAndHeaderParser and Http1ServerParser. This issue is fixed in versions 0.23.18 and 1.0.0-M42.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-444\", \"description\": \"CWE-444: Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027)\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-09-14T17:33:49.671Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-73494\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-09-14T20:05:52.181Z\", \"dateReserved\": \"2026-08-12T19:00:33.735Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-09-14T17:33:49.671Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

FKIE_CVE-2026-73494

Vulnerability from fkie_nvd - Published: 2026-09-14 18:19 - Updated: 2026-09-14 20:16

Severity

7.4 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/http4s/blaze/commit/3f7c022e306631b006dcb43a1d7f65c0d1966f17
	security-advisories@github.com	https://github.com/http4s/blaze/commit/4eec2007806aa9acfefb00ebb636ddc39a147a96
	security-advisories@github.com	https://github.com/http4s/blaze/commit/927b67753a78c13c4445dac9307f511f5c4878c3
	security-advisories@github.com	https://github.com/http4s/blaze/commit/a54bc9cd31758335c7f24e29763622fd03fcf734
	security-advisories@github.com	https://github.com/http4s/blaze/commit/c47d9675f87603f11b32a11d503626bdf9be5c7a
	security-advisories@github.com	https://github.com/http4s/blaze/commit/e871ebb1d27f50c98fd56988526ce42d0fee74d6
	security-advisories@github.com	https://github.com/http4s/blaze/releases/tag/v0.23.18
	security-advisories@github.com	https://github.com/http4s/blaze/releases/tag/v1.0.0-M42
	security-advisories@github.com	https://github.com/http4s/blaze/security/advisories/GHSA-mhvj-jhpq-885v

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "blaze",
          "vendor": "http4s",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.23.18"
            },
            {
              "status": "affected",
              "version": "\u003e= 1.0.0-M1, \u003c 1.0.0-M42"
            }
          ]
        },
        {
          "product": "blaze-http_2.13",
          "vendor": "org.http4s",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.23.18"
            },
            {
              "status": "affected",
              "version": "\u003e= 1.0.0-M1, \u003c 1.0.0-M42"
            }
          ]
        },
        {
          "product": "blaze-http_3",
          "vendor": "org.http4s",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.23.18"
            },
            {
              "status": "affected",
              "version": "\u003e= 1.0.0-M1, \u003c 1.0.0-M42"
            }
          ]
        },
        {
          "product": "http4s-blaze-server_2.13",
          "vendor": "org.http4s",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.23.18"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and from 1.0.0-M1 until 1.0.0-M42, five HTTP/1.1 conformance laxities in the hand-written Java parser under http/src/main/java/org/http4s/blaze/http/parser/ can cause blaze to derive a different request boundary than a stricter fronting intermediary. A default BlazeServerBuilder accepts invalid or valueless header field names that violate tchar syntax, obsolete folded field lines (obs-fold), unsupported Transfer-Encoding values, duplicate Content-Length fields, and requests containing both Transfer-Encoding and Content-Length. If a lenient or legacy proxy forwards the malformed bytes but interprets them differently, the disagreement can permit front-end authorization bypass, response-queue poisoning on pooled backend connections, or cache poisoning. Exploitation requires a pair of disagreeing parsers; no non-default blaze configuration is required. The affected checks are enforced in BodyAndHeaderParser and Http1ServerParser. This issue is fixed in versions 0.23.18 and 1.0.0-M42."
    }
  ],
  "id": "CVE-2026-73494",
  "lastModified": "2026-09-14T20:16:50.707",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 7.4,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 5.2,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-73494",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-14T19:21:20.842876Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-14T18:19:58.857",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/http4s/blaze/commit/3f7c022e306631b006dcb43a1d7f65c0d1966f17"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/http4s/blaze/commit/4eec2007806aa9acfefb00ebb636ddc39a147a96"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/http4s/blaze/commit/927b67753a78c13c4445dac9307f511f5c4878c3"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/http4s/blaze/commit/a54bc9cd31758335c7f24e29763622fd03fcf734"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/http4s/blaze/commit/c47d9675f87603f11b32a11d503626bdf9be5c7a"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/http4s/blaze/commit/e871ebb1d27f50c98fd56988526ce42d0fee74d6"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/http4s/blaze/releases/tag/v0.23.18"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/http4s/blaze/releases/tag/v1.0.0-M42"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/http4s/blaze/security/advisories/GHSA-mhvj-jhpq-885v"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-444"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-MHVJ-JHPQ-885V

Vulnerability from github – Published: 2026-07-24 22:26 – Updated: 2026-08-12 21:12

Summary

blaze: Multiple HTTP/1.1 request-smuggling primitives in blaze's Java wire parser

Details

Summary

Five independent HTTP/1.1 conformance laxities in blaze's hand-written Java parser (http/src/main/java/org/http4s/blaze/http/parser/) cause request-boundary disagreement with a stricter intermediary. All are reachable from a default BlazeServerBuilder with no non-default configuration.

Impact

Actual exploitability depends on the fronting proxy — a boundary disagreement requires a pair of parsers that disagree. Where the proxy forwards the malformed bytes and derives a different message boundary, the consequences are the standard set: front-end ACL/auth bypass, response-queue poisoning on pooled backend connections, and cache poisoning. Risk concentrates on lenient or legacy intermediaries.

Workarounds

Deploy behind an RFC-strict reverse proxy (nginx, HAProxy, Envoy, ALB) that rejects or re-serializes malformed requests at the edge; this neutralizes most of these for deployments that cannot upgrade immediately.

Severity

7.4 (High)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.23.17"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:http4s-blaze-server_2.13"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.23.18"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.23.17"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:blaze-http_2.13"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.23.18"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.23.17"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:blaze-http_3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.23.18"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.0.0-M41"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:blaze-http_3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.0.0-M1"
            },
            {
              "fixed": "1.0.0-M42"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.0.0-M41"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.http4s:blaze-http_2.13"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.0.0-M1"
            },
            {
              "fixed": "1.0.0-M42"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-73494"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-24T22:26:27Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n  Five independent HTTP/1.1 conformance laxities in blaze\u0027s hand-written Java parser (`http/src/main/java/org/http4s/blaze/http/parser/`) cause request-boundary disagreement with a stricter intermediary. All are reachable from a default `BlazeServerBuilder` with no non-default configuration.\n\n### Impact\nActual exploitability depends on the fronting proxy \u2014 a boundary disagreement requires a *pair* of parsers that disagree. Where the proxy forwards the malformed bytes and derives a different message boundary, the consequences are the standard set: front-end ACL/auth bypass, response-queue poisoning on pooled backend connections, and cache poisoning. Risk concentrates on lenient or legacy intermediaries.\n\n### Workarounds\n  Deploy behind an RFC-strict reverse proxy (nginx, HAProxy, Envoy, ALB) that rejects or re-serializes malformed requests at the edge; this neutralizes most of these for deployments that cannot upgrade immediately.",
  "id": "GHSA-mhvj-jhpq-885v",
  "modified": "2026-08-12T21:12:10Z",
  "published": "2026-07-24T22:26:27Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/security/advisories/GHSA-mhvj-jhpq-885v"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/commit/3f7c022e306631b006dcb43a1d7f65c0d1966f17"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/commit/4eec2007806aa9acfefb00ebb636ddc39a147a96"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/commit/927b67753a78c13c4445dac9307f511f5c4878c3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/commit/a54bc9cd31758335c7f24e29763622fd03fcf734"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/commit/c47d9675f87603f11b32a11d503626bdf9be5c7a"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/commit/e871ebb1d27f50c98fd56988526ce42d0fee74d6"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/http4s/blaze"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/releases/tag/v0.23.18"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/releases/tag/v1.0.0-M42"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "blaze: Multiple HTTP/1.1 request-smuggling primitives in blaze\u0027s Java wire parser"
}

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.

Detection rules are retrieved from Rulezet.

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.

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.

Action not permitted

CVE-2026-73494 (GCVE-0-2026-73494)

FKIE_CVE-2026-73494

GHSA-MHVJ-JHPQ-885V

Summary

Impact

Workarounds

Tags

Sightings

Nomenclature

Related by attack behaviour