UBUNTU-CVE-2026-59980 (CVE-2026-59980)

Vulnerability from osv_ubuntu – Published: 2026-09-24 00:00 – Updated: 2026-09-24 00:00 – Source website
VLAI
Details

hpack is an HTTP/2 Header Encoding for Python. Prior to version 4.2.0, unbounded variable integer decoding can cause run-away computation on malformed input leading to O(n^2) runtime, effectively blocking further processing with large enough unsanitized input. A fix is available in python-hyper/hpack v4.2.0 to restricted variable integer decoding to uint32 to prevent run-away computation. As a workaround, sanitize input to hpack decoder for long sequences of 0xFF values to prevent malicious use.

Severity
6.3 (Medium)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python-hpack",
            "binary_version": "2.1.0-1"
          },
          {
            "binary_name": "python3-hpack",
            "binary_version": "2.1.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "python-hpack",
        "purl": "pkg:deb/ubuntu/python-hpack@2.1.0-1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.1.0-1",
        "2.0.1-1",
        "2.1.0-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python-hpack",
            "binary_version": "3.0.0-2"
          },
          {
            "binary_name": "python3-hpack",
            "binary_version": "3.0.0-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "python-hpack",
        "purl": "pkg:deb/ubuntu/python-hpack@3.0.0-2?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.0.0-1",
        "3.0.0-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-hpack",
            "binary_version": "3.0.0-4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "python-hpack",
        "purl": "pkg:deb/ubuntu/python-hpack@3.0.0-4?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.0.0-3",
        "3.0.0-4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-hpack",
            "binary_version": "4.0.0-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "python-hpack",
        "purl": "pkg:deb/ubuntu/python-hpack@4.0.0-2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.0.0-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-hpack",
            "binary_version": "4.0.0-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "python-hpack",
        "purl": "pkg:deb/ubuntu/python-hpack@4.0.0-2?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.0.0-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-hpack",
            "binary_version": "4.0.0-3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "python-hpack",
        "purl": "pkg:deb/ubuntu/python-hpack@4.0.0-3?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.0.0-3"
      ]
    }
  ],
  "aliases": [],
  "details": "hpack is an HTTP/2 Header Encoding for Python. Prior to version 4.2.0, unbounded variable integer decoding can cause run-away computation on malformed input leading to O(n^2) runtime, effectively blocking further processing with large enough unsanitized input. A fix is available in python-hyper/hpack v4.2.0 to restricted variable integer decoding to uint32 to prevent run-away computation. As a workaround, sanitize input to hpack decoder for long sequences of `0xFF` values to prevent malicious use.",
  "id": "UBUNTU-CVE-2026-59980",
  "modified": "2026-09-24T00:00:00Z",
  "published": "2026-09-24T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-59980"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-59980"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/python-hyper/hpack/security/advisories/GHSA-8v8h-hg4w-mvq2"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/python-hyper/hpack/commit/8cfb02c547740e16dbfe7aba77bad84b297cec2c"
    },
    {
      "type": "REPORT",
      "url": "https://cs.opensource.google/go/x/net/+/master:http2/hpack/hpack.go;l=468;drc=8e2b117aee74f6b86c207a808b0255de45c0a18a"
    },
    {
      "type": "REPORT",
      "url": "https://docs.rs/http2/0.5.19/src/http2/hpack/decoder.rs.html#403"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/python-hyper/hpack/commit/8cfb02c547740e16dbfe7aba77bad84b297cec2c"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-59980"
  ]
}



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