ubuntu-cve-2026-55204
Vulnerability from osv_ubuntu
Published
2026-06-19 00:00
Modified
2026-06-24 09:03
Summary
Details

HAProxy through 3.4.0, fixed in commit 9a6d1fe, contains a null pointer dereference vulnerability in hpack_dht_insert() within src/hpack-tbl.c that fails to validate the return value of hpack_dht_defrag() when the memory pool is exhausted. An attacker can trigger HPACK dynamic table insertions under memory pressure to dereference a NULL pointer and crash HAProxy worker processes, causing denial of service.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "haproxy",
            "binary_version": "1.6.3-1ubuntu0.3+esm2"
          },
          {
            "binary_name": "vim-haproxy",
            "binary_version": "1.6.3-1ubuntu0.3+esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "haproxy",
        "purl": "pkg:deb/ubuntu/haproxy@1.6.3-1ubuntu0.3+esm2?arch=source\u0026distro=esm-infra/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.5.14-1",
        "1.5.15-1",
        "1.6.2-1",
        "1.6.2-2",
        "1.6.2-2ubuntu1",
        "1.6.2-2ubuntu3",
        "1.6.3-1",
        "1.6.3-1ubuntu0.1",
        "1.6.3-1ubuntu0.2",
        "1.6.3-1ubuntu0.3",
        "1.6.3-1ubuntu0.3+esm1",
        "1.6.3-1ubuntu0.3+esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "haproxy",
            "binary_version": "1.8.8-1ubuntu0.13+esm3"
          },
          {
            "binary_name": "vim-haproxy",
            "binary_version": "1.8.8-1ubuntu0.13+esm3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "haproxy",
        "purl": "pkg:deb/ubuntu/haproxy@1.8.8-1ubuntu0.13+esm3?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.7.9-1ubuntu1",
        "1.7.9-1ubuntu2",
        "1.8.4-1",
        "1.8.7-1",
        "1.8.8-1",
        "1.8.8-1ubuntu0.1",
        "1.8.8-1ubuntu0.2",
        "1.8.8-1ubuntu0.3",
        "1.8.8-1ubuntu0.4",
        "1.8.8-1ubuntu0.6",
        "1.8.8-1ubuntu0.7",
        "1.8.8-1ubuntu0.8",
        "1.8.8-1ubuntu0.9",
        "1.8.8-1ubuntu0.10",
        "1.8.8-1ubuntu0.11",
        "1.8.8-1ubuntu0.13",
        "1.8.8-1ubuntu0.13+esm2",
        "1.8.8-1ubuntu0.13+esm3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "haproxy",
            "binary_version": "2.0.33-0ubuntu0.1"
          },
          {
            "binary_name": "vim-haproxy",
            "binary_version": "2.0.33-0ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "haproxy",
        "purl": "pkg:deb/ubuntu/haproxy@2.0.33-0ubuntu0.1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "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",
        "2.0.13-2ubuntu0.3",
        "2.0.13-2ubuntu0.5",
        "2.0.29-0ubuntu1",
        "2.0.29-0ubuntu1.1",
        "2.0.29-0ubuntu1.3",
        "2.0.31-0ubuntu0.1",
        "2.0.31-0ubuntu0.2",
        "2.0.31-0ubuntu0.3",
        "2.0.33-0ubuntu0.1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "haproxy",
            "binary_version": "2.4.30-0ubuntu0.22.04.2"
          },
          {
            "binary_name": "vim-haproxy",
            "binary_version": "2.4.30-0ubuntu0.22.04.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "haproxy",
        "purl": "pkg:deb/ubuntu/haproxy@2.4.30-0ubuntu0.22.04.2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.4.30-0ubuntu0.22.04.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.2.9-2ubuntu2",
        "2.4.8-1",
        "2.4.8-2ubuntu3",
        "2.4.11-1ubuntu1",
        "2.4.12-1ubuntu1",
        "2.4.12-1ubuntu2",
        "2.4.13-1ubuntu1",
        "2.4.14-1ubuntu1",
        "2.4.18-0ubuntu1",
        "2.4.18-0ubuntu1.1",
        "2.4.18-0ubuntu1.2",
        "2.4.18-0ubuntu1.3",
        "2.4.22-0ubuntu0.22.04.1",
        "2.4.22-0ubuntu0.22.04.2",
        "2.4.22-0ubuntu0.22.04.3",
        "2.4.24-0ubuntu0.22.04.1",
        "2.4.24-0ubuntu0.22.04.2",
        "2.4.24-0ubuntu0.22.04.3",
        "2.4.29-0ubuntu0.22.04.1",
        "2.4.30-0ubuntu0.22.04.1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "haproxy",
            "binary_version": "2.8.16-0ubuntu0.24.04.3"
          },
          {
            "binary_name": "vim-haproxy",
            "binary_version": "2.8.16-0ubuntu0.24.04.3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "haproxy",
        "purl": "pkg:deb/ubuntu/haproxy@2.8.16-0ubuntu0.24.04.3?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.8.16-0ubuntu0.24.04.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.6.15-1ubuntu2",
        "2.8.5-1ubuntu1",
        "2.8.5-1ubuntu2",
        "2.8.5-1ubuntu3",
        "2.8.5-1ubuntu3.1",
        "2.8.5-1ubuntu3.2",
        "2.8.5-1ubuntu3.3",
        "2.8.5-1ubuntu3.4",
        "2.8.15-0ubuntu0.24.04.1",
        "2.8.16-0ubuntu0.24.04.1",
        "2.8.16-0ubuntu0.24.04.2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "haproxy",
            "binary_version": "3.0.12-0ubuntu0.25.10.5"
          },
          {
            "binary_name": "vim-haproxy",
            "binary_version": "3.0.12-0ubuntu0.25.10.5"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "haproxy",
        "purl": "pkg:deb/ubuntu/haproxy@3.0.12-0ubuntu0.25.10.5?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.0.12-0ubuntu0.25.10.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.0.8-1ubuntu1",
        "3.0.8-1ubuntu1.1",
        "3.0.10-1ubuntu1",
        "3.0.10-1ubuntu2",
        "3.0.10-1ubuntu3",
        "3.0.12-0ubuntu0.25.10.1",
        "3.0.12-0ubuntu0.25.10.3",
        "3.0.12-0ubuntu0.25.10.4"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "haproxy",
            "binary_version": "3.2.9-1ubuntu2.2"
          },
          {
            "binary_name": "vim-haproxy",
            "binary_version": "3.2.9-1ubuntu2.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "haproxy",
        "purl": "pkg:deb/ubuntu/haproxy@3.2.9-1ubuntu2.2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.2.9-1ubuntu2.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.0.10-1ubuntu3",
        "3.2.9-1ubuntu1",
        "3.2.9-1ubuntu2",
        "3.2.9-1ubuntu2.1"
      ]
    }
  ],
  "aliases": [],
  "details": "HAProxy through  3.4.0, fixed in commit 9a6d1fe, contains a null pointer dereference vulnerability in hpack_dht_insert() within src/hpack-tbl.c that fails to validate the return value of hpack_dht_defrag() when the memory pool is exhausted. An attacker can trigger HPACK dynamic table insertions under memory pressure to dereference a NULL pointer and crash HAProxy worker processes, causing denial of service.",
  "id": "UBUNTU-CVE-2026-55204",
  "modified": "2026-06-24T09:03:12Z",
  "published": "2026-06-19T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-55204"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-55204"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8459-1"
    }
  ],
  "related": [
    "USN-8459-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-55204"
  ]
}



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