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CVE-2026-84642

CVE-2026-84642 · Allowed UNC hostnames for attachments interpreted as a regular expression

This page contains facts from public vulnerability sources. Check the original advisory before updating.

The values of the mail.allowed_attachment_hostnames advanced config setting were used in a regular expression without escaping. For some possible valid hostnames, this could allow certain unintended hostnames to also match and serve remote attachments. This vulnerability was fixed in Thunderbird 155 and Thunderbird 153.2.

CVSS 7.5 · High · EPSS 0.4%

Published
Updated

Stack: system

Affected products and versions

  • thunderbird

    Versions
    • ≥ 153.2, ≤ 153.*: Not affected (rpm)
    • ≥ 155: Not affected (rpm)

    No fix published

  • thunderbird Ubuntu:22.04:LTS

    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
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • thunderbird Ubuntu:24.04:LTS

    Versions
    • 1:115.3.1+build1-0ubuntu1
    • 1:115.4.1+build1-0ubuntu1
    • 1:115.4.3+build1-0ubuntu1
    • 1:115.5.0+build1-0ubuntu1
    • 1:115.5.1+build1-0ubuntu1
    • 1:115.5.2+build2-0ubuntu1
    • 1:115.6.0+build1-0ubuntu1
    • 1:115.6.0+build2-0ubuntu1
    • 1:115.6.1+build1-0ubuntu1
    • 1:115.8.0+build1-0ubuntu1
    • 1:115.8.1+build1+snap2
    • 1:115.8.1+build1+snap3
    • 2:1snap1-0ubuntu1
    • 2:1snap1-0ubuntu3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • thunderbird Ubuntu:26.10

    Versions
    • 2:1snap1-0ubuntu5
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • thunderbird Ubuntu:26.04:LTS

    Versions
    • 2:1snap1-0ubuntu3
    • 2:1snap1-0ubuntu4
    • 2:1snap1-0ubuntu5
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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