Vulnerability-Lookup

GHSA-5MP8-RQ5M-PJ7M

Vulnerability from github – Published: 2026-04-13 18:30 – Updated: 2026-04-22 18:31

Details

An issue was discovered in HAProxy before 3.3.6. The HTTP/3 parser does not check that the received body length matches a previously announced content-length when the stream is closed via a frame with an empty payload. This can cause desynchronization issues with the backend server and could be used for request smuggling. The earliest affected version is 2.6.

Severity ?

4.0 (Medium)


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

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-33555"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-130"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-13T17:16:28Z",
    "severity": "MODERATE"
  },
  "details": "An issue was discovered in HAProxy before 3.3.6. The HTTP/3 parser does not check that the received body length matches a previously announced content-length when the stream is closed via a frame with an empty payload. This can cause desynchronization issues with the backend server and could be used for request smuggling. The earliest affected version is 2.6.",
  "id": "GHSA-5mp8-rq5m-pj7m",
  "modified": "2026-04-22T18:31:38Z",
  "published": "2026-04-13T18:30:41Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33555"
    },
    {
      "type": "WEB",
      "url": "https://github.com/haproxy/haproxy/commit/05a295441c621089ffa4318daf0dbca2dd756a84"
    },
    {
      "type": "WEB",
      "url": "https://r3verii.github.io/cve/2026/04/14/haproxy-h3-standalone-fin-smuggling.html"
    },
    {
      "type": "WEB",
      "url": "https://www.haproxy.com/documentation/haproxy-aloha/changelog"
    },
    {
      "type": "WEB",
      "url": "https://www.haproxy.org"
    },
    {
      "type": "WEB",
      "url": "https://www.mail-archive.com/haproxy@formilux.org/msg46752.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-33555 (GCVE-0-2026-33555)

Vulnerability from cvelistv5 – Published: 2026-04-13 00:00 – Updated: 2026-04-22 18:43

Summary

Severity ?

4 (Medium)


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

CWE

CWE-130 - Improper Handling of Length Parameter Inconsistency

Assigner

mitre

References

URL

Tags

	https://www.haproxy.org
	https://www.haproxy.com/documentation/haproxy-alo…
	https://github.com/haproxy/haproxy/commit/05a2954…
	https://www.mail-archive.com/haproxy@formilux.org…
	https://r3verii.github.io/cve/2026/04/14/haproxy-…

Impacted products

	Vendor	Product	Version
	HAProxy	HAProxy	Affected: 2.6 , < 3.3.6 (custom)

Show details on NVD website

JSON

To clipboard

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  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-33555",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-22T18:42:59.239377Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-22T18:43:17.553Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
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            "url": "https://r3verii.github.io/cve/2026/04/14/haproxy-h3-standalone-fin-smuggling.html"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
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          "defaultStatus": "unaffected",
          "product": "HAProxy",
          "vendor": "HAProxy",
          "versions": [
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              "status": "affected",
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            }
          ]
        }
      ],
      "cpeApplicability": [
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                  "criteria": "cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "3.3.6",
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                }
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        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
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            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N",
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}

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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-5MP8-RQ5M-PJ7M

CVE-2026-33555 (GCVE-0-2026-33555)

Tags

Sightings

Nomenclature