ubuntu-cve-2026-4691
Vulnerability from osv_ubuntu
Published
2026-03-24 13:16
Modified
2026-06-30 16:18
Summary
Details

Use-after-free in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmozjs-52-0",
            "binary_version": "52.9.1-0ubuntu0.18.04.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "mozjs52",
        "purl": "pkg:deb/ubuntu/mozjs52@52.9.1-0ubuntu0.18.04.1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "52.3.1-0ubuntu3",
        "52.3.1-7fakesync1",
        "52.8.1-0ubuntu0.18.04.1",
        "52.9.1-0ubuntu0.18.04.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmozjs-38-0",
            "binary_version": "38.8.0~repack1-0ubuntu4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "mozjs38",
        "purl": "pkg:deb/ubuntu/mozjs38@38.8.0~repack1-0ubuntu4?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "38.8.0~repack1-0ubuntu1",
        "38.8.0~repack1-0ubuntu3",
        "38.8.0~repack1-0ubuntu4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmozjs-68-0",
            "binary_version": "68.6.0-1ubuntu1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "mozjs68",
        "purl": "pkg:deb/ubuntu/mozjs68@68.6.0-1ubuntu1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "68.5.0-1~fakesync",
        "68.5.0-2~fakesync",
        "68.6.0-1",
        "68.6.0-1ubuntu1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmozjs-52-0",
            "binary_version": "52.9.1-1ubuntu3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "mozjs52",
        "purl": "pkg:deb/ubuntu/mozjs52@52.9.1-1ubuntu3?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "52.9.1-1build1",
        "52.9.1-1ubuntu3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmozjs-102-0",
            "binary_version": "102.15.1-0ubuntu0.22.04.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "mozjs102",
        "purl": "pkg:deb/ubuntu/mozjs102@102.15.1-0ubuntu0.22.04.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "102.11.0-0ubuntu0.22.04.1",
        "102.12.0-0ubuntu0.22.04.1",
        "102.13.0-0ubuntu0.22.04.1",
        "102.15.1-0ubuntu0.22.04.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmozjs-78-0",
            "binary_version": "78.15.0-4ubuntu1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "mozjs78",
        "purl": "pkg:deb/ubuntu/mozjs78@78.15.0-4ubuntu1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "78.13.0-1",
        "78.15.0-2",
        "78.15.0-4ubuntu1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmozjs-91-0",
            "binary_version": "91.10.0-0ubuntu1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "mozjs91",
        "purl": "pkg:deb/ubuntu/mozjs91@91.10.0-0ubuntu1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "91.5.1-0ubuntu1",
        "91.6.0-1",
        "91.6.0-2",
        "91.7.0-2",
        "91.10.0-0ubuntu1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "thunderbird",
            "binary_version": "1:140.7.1+build1-0ubuntu0.22.04.1"
          },
          {
            "binary_name": "thunderbird-gnome-support",
            "binary_version": "1:140.7.1+build1-0ubuntu0.22.04.1"
          },
          {
            "binary_name": "thunderbird-mozsymbols",
            "binary_version": "1:140.7.1+build1-0ubuntu0.22.04.1"
          },
          {
            "binary_name": "xul-ext-calendar-timezones",
            "binary_version": "1:140.7.1+build1-0ubuntu0.22.04.1"
          },
          {
            "binary_name": "xul-ext-gdata-provider",
            "binary_version": "1:140.7.1+build1-0ubuntu0.22.04.1"
          },
          {
            "binary_name": "xul-ext-lightning",
            "binary_version": "1:140.7.1+build1-0ubuntu0.22.04.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "thunderbird",
        "purl": "pkg:deb/ubuntu/thunderbird@1:140.7.1+build1-0ubuntu0.22.04.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:91.1.2+build1-0ubuntu1",
        "1:91.3.0+build2-0ubuntu1",
        "1:91.3.1+build1-0ubuntu1",
        "1:91.3.2+build1-0ubuntu1",
        "1:91.4.0+build1.1-0ubuntu1",
        "1:91.4.0+build2-0ubuntu1",
        "1:91.5.0+build1-0ubuntu1",
        "1:91.5.1+build1-0ubuntu1",
        "1:91.6.1+build1-0ubuntu1",
        "1:91.7.0+build1-0ubuntu1",
        "1:91.7.0+build2-0ubuntu1",
        "1:91.8.0+build2-0ubuntu1",
        "1:91.9.1+build1-0ubuntu0.22.04.1",
        "1:91.11.0+build2-0ubuntu0.22.04.1",
        "1:102.2.2+build1-0ubuntu0.22.04.1",
        "1:102.4.2+build2-0ubuntu0.22.04.1",
        "1:102.7.1+build2-0ubuntu0.22.04.1",
        "1:102.8.0+build2-0ubuntu0.22.04.1",
        "1:102.9.0+build1-0ubuntu0.22.04.1",
        "1:102.10.0+build2-0ubuntu0.22.04.1",
        "1:102.11.0+build1-0ubuntu0.22.04.1",
        "1:102.13.0+build1-0ubuntu0.22.04.1",
        "1:102.15.0+build1-0ubuntu0.22.04.1",
        "1:102.15.1+build1-0ubuntu0.22.04.1",
        "1:115.3.1+build1-0ubuntu0.22.04.2",
        "1:115.4.1+build1-0ubuntu0.22.04.1",
        "1:115.5.0+build1-0ubuntu0.22.04.1",
        "1:115.6.0+build2-0ubuntu0.22.04.1",
        "1:115.8.1+build1-0ubuntu0.22.04.1",
        "1:115.9.0+build1-0ubuntu0.22.04.1",
        "1:115.10.1+build1-0ubuntu0.22.04.1",
        "1:115.11.0+build2-0ubuntu0.22.04.1",
        "1:115.12.0+build3-0ubuntu0.22.04.1",
        "1:115.13.0+build5-0ubuntu0.22.04.1",
        "1:115.15.0+build1-0ubuntu0.22.04.1",
        "1:115.16.0+build2-0ubuntu0.22.04.1",
        "1:115.18.0+build1-0ubuntu0.22.04.1",
        "1:128.12.0+build1-0ubuntu0.22.04.1",
        "1:140.7.1+build1-0ubuntu0.22.04.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmozjs-102-0t64",
            "binary_version": "102.15.1-3ubuntu2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "mozjs102",
        "purl": "pkg:deb/ubuntu/mozjs102@102.15.1-3ubuntu2?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "102.15.1-1",
        "102.15.1-3ubuntu2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmozjs-115-0t64",
            "binary_version": "115.10.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "mozjs115",
        "purl": "pkg:deb/ubuntu/mozjs115@115.10.0-1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "115.3.0-0ubuntu1",
        "115.4.0-2",
        "115.5.0-1",
        "115.6.0-1",
        "115.7.0-4",
        "115.8.0-1",
        "115.9.0-1",
        "115.9.0-1build1",
        "115.10.0-1"
      ]
    }
  ],
  "aliases": [],
  "details": "Use-after-free in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.",
  "id": "UBUNTU-CVE-2026-4691",
  "modified": "2026-06-30T16:18:35Z",
  "published": "2026-03-24T13:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-4691"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-4691"
    },
    {
      "type": "REPORT",
      "url": "https://www.mozilla.org/en-US/security/advisories/mfsa2026-20/#CVE-2026-4691"
    },
    {
      "type": "REPORT",
      "url": "https://www.mozilla.org/en-US/security/advisories/mfsa2026-22/#CVE-2026-4691"
    },
    {
      "type": "REPORT",
      "url": "https://www.mozilla.org/en-US/security/advisories/mfsa2026-24/#CVE-2026-4691"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2017512"
    },
    {
      "type": "REPORT",
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-20/"
    },
    {
      "type": "REPORT",
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-21/"
    },
    {
      "type": "REPORT",
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-22/"
    },
    {
      "type": "REPORT",
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-23/"
    },
    {
      "type": "REPORT",
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-24/"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-4691"
  ]
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.