USN-7955-2 (UBUNTU-CVE-2026-21441)

Vulnerability from osv_ubuntu – Published: 2026-01-19 11:57 – Updated: 2026-06-30 15:54 – Source website
VLAI
Summary
python-urllib3 regression
Details

USN-7955-1 fixed vulnerabilities in urllib3. The update introduced a regression in response streaming on Ubuntu 20.04 LTS and Ubuntu 22.04 LTS. This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

It was discovered that urllib3 incorrectly handled decompression during HTTP redirects. An attacker could possibly use this issue to cause urllib3 to use excessive resources, causing a denial of service.

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-21441",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H",
                  "type": "CVSS_V4"
                },
                {
                  "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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:Pro:20.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "python3-urllib3",
            "binary_version": "1.25.8-2ubuntu0.4+esm4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "python-urllib3",
        "purl": "pkg:deb/ubuntu/python-urllib3@1.25.8-2ubuntu0.4+esm4?arch=source\u0026distro=esm-infra/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.25.8-2ubuntu0.4+esm4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.24.1-1ubuntu1",
        "1.24.1-1ubuntu2",
        "1.25.8-1",
        "1.25.8-2",
        "1.25.8-2ubuntu0.1",
        "1.25.8-2ubuntu0.2",
        "1.25.8-2ubuntu0.3",
        "1.25.8-2ubuntu0.4",
        "1.25.8-2ubuntu0.4+esm1",
        "1.25.8-2ubuntu0.4+esm2",
        "1.25.8-2ubuntu0.4+esm3"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-21441",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H",
                  "type": "CVSS_V4"
                },
                {
                  "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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:22.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "python3-urllib3",
            "binary_version": "1.26.5-1~exp1ubuntu0.6"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "python-urllib3",
        "purl": "pkg:deb/ubuntu/python-urllib3@1.26.5-1~exp1ubuntu0.6?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.26.5-1~exp1ubuntu0.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.26.5-1~exp1",
        "1.26.5-1~exp1ubuntu0.1",
        "1.26.5-1~exp1ubuntu0.2",
        "1.26.5-1~exp1ubuntu0.3",
        "1.26.5-1~exp1ubuntu0.4",
        "1.26.5-1~exp1ubuntu0.5"
      ]
    }
  ],
  "aliases": [],
  "details": "USN-7955-1 fixed vulnerabilities in urllib3. The update introduced a\nregression in response streaming on Ubuntu 20.04 LTS and Ubuntu 22.04 LTS.\nThis update fixes the problem.\n\nWe apologize for the inconvenience.\n\nOriginal advisory details:\n\n It was discovered that urllib3 incorrectly handled decompression during\n HTTP redirects. An attacker could possibly use this issue to cause urllib3\n to use excessive resources, causing a denial of service.",
  "id": "USN-7955-2",
  "modified": "2026-06-30T15:54:46Z",
  "published": "2026-01-19T11:57:37Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-7955-2"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-21441"
    },
    {
      "type": "REPORT",
      "url": "https://bugs.launchpad.net/bugs/2138420"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "python-urllib3 regression",
  "upstream": [
    "UBUNTU-CVE-2026-21441"
  ]
}



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