Vulnerability-Lookup

USN-5063-1 (UBUNTU-CVE-2021-40346)

Vulnerability from osv_ubuntu – Published: 2021-09-08 11:06 – Updated: 2026-02-10 04:42 – Source website

Summary

haproxy vulnerabilities

Details

Ori Hollander discovered that HAProxy incorrectly handled HTTP header name length encoding. A remote attacker could possibly use this issue to inject a duplicate content-length header and perform request smuggling attacks.

References

URL

Type

	https://ubuntu.com/security/notices/USN-5063-1	ADVISORY
	https://ubuntu.com/security/CVE-2021-40346	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2021-40346",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:20.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "haproxy",
            "binary_version": "2.0.13-2ubuntu0.3"
          },
          {
            "binary_name": "vim-haproxy",
            "binary_version": "2.0.13-2ubuntu0.3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "haproxy",
        "purl": "pkg:deb/ubuntu/haproxy@2.0.13-2ubuntu0.3?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.0.13-2ubuntu0.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.0.5-1",
        "2.0.8-1",
        "2.0.9-1",
        "2.0.10-1",
        "2.0.10-1ubuntu1",
        "2.0.11-1ubuntu1",
        "2.0.12-1ubuntu2",
        "2.0.13-1ubuntu2",
        "2.0.13-2",
        "2.0.13-2ubuntu0.1",
        "2.0.13-2ubuntu0.2"
      ]
    }
  ],
  "aliases": [],
  "details": "Ori Hollander discovered that HAProxy incorrectly handled HTTP header name\nlength encoding. A remote attacker could possibly use this issue to inject\na duplicate content-length header and perform request smuggling attacks.\n",
  "id": "USN-5063-1",
  "modified": "2026-02-10T04:42:18Z",
  "published": "2021-09-08T11:06:21Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-5063-1"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-40346"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "haproxy vulnerabilities",
  "upstream": [
    "UBUNTU-CVE-2021-40346"
  ]
}

UBUNTU-CVE-2021-40346 (CVE-2021-40346)

Vulnerability from osv_ubuntu – Published: 2021-09-07 15:00 – Updated: 2025-09-08 16:47 – Source website

Details

An integer overflow exists in HAProxy 2.0 through 2.5 in htx_add_header that can be exploited to perform an HTTP request smuggling attack, allowing an attacker to bypass all configured http-request HAProxy ACLs and possibly other ACLs.

Severity

7.5 (High)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2021-40346	REPORT
	https://www.mail-archive.com/haproxy@formilux.org…	REPORT
	https://ubuntu.com/security/notices/USN-5063-1	ADVISORY
	https://www.cve.org/CVERecord?id=CVE-2021-40346	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "haproxy",
            "binary_version": "2.0.13-2ubuntu0.3"
          },
          {
            "binary_name": "vim-haproxy",
            "binary_version": "2.0.13-2ubuntu0.3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "haproxy",
        "purl": "pkg:deb/ubuntu/haproxy@2.0.13-2ubuntu0.3?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.0.13-2ubuntu0.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.0.5-1",
        "2.0.8-1",
        "2.0.9-1",
        "2.0.10-1",
        "2.0.10-1ubuntu1",
        "2.0.11-1ubuntu1",
        "2.0.12-1ubuntu2",
        "2.0.13-1ubuntu2",
        "2.0.13-2",
        "2.0.13-2ubuntu0.1",
        "2.0.13-2ubuntu0.2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "haproxy",
            "binary_version": "2.2.9-2ubuntu2"
          },
          {
            "binary_name": "vim-haproxy",
            "binary_version": "2.2.9-2ubuntu2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "haproxy",
        "purl": "pkg:deb/ubuntu/haproxy@2.2.9-2ubuntu2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.2.9-2ubuntu2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [],
  "details": "An integer overflow exists in HAProxy 2.0 through 2.5 in htx_add_header that can be exploited to perform an HTTP request smuggling attack, allowing an attacker to bypass all configured http-request HAProxy ACLs and possibly other ACLs.",
  "id": "UBUNTU-CVE-2021-40346",
  "modified": "2025-09-08T16:47:21Z",
  "published": "2021-09-07T15:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-40346"
    },
    {
      "type": "REPORT",
      "url": "https://www.mail-archive.com/haproxy@formilux.org/msg41114.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-5063-1"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-40346"
    }
  ],
  "related": [
    "USN-5063-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2021-40346"
  ]
}

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.