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

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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.

Action not permitted

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

FKIE_CVE-2026-73494

GHSA-MHVJ-JHPQ-885V

Summary

Impact

Workarounds

Tags

Sightings

Nomenclature