CVE-2026-84642

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.

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.

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.

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.

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.

Uninitialized memory in MIME parsing. (CVE-2026-84639) One byte overflow read in mail parser. (CVE-2026-84640) Information disclosure due to malicious IMAP server response. (CVE-2026-84641) Calendar invitation attachments could launch local executables. (CVE-2026-84637) Allowed UNC hostnames for attachments interpreted as a regular expression. (CVE-2026-84642) Sandbox escape in the Remote Settings Client component. (CVE-2026-75874) Privilege escalation in the DOM: Workers component. (CVE-2026-16365) Use-after-free in the JavaScript: GC component. (CVE-2026-84118) Sandbox escape due to use-after-free in the DOM: Navigation component. (CVE-2026-84119) Use-after-free in the Audio/Video component. (CVE-2026-84120) Sandbox escape due to use-after-free in the DOM: Security component. (CVE-2026-84121) Use-after-free in the Audio/Video component. (CVE-2026-84122) Privilege escalation due to use-after-free in the Graphics: WebGPU component. (CVE-2026-84123) Use-after-free in the DOM: Core & HTML component. (CVE-2026-84124) Use-after-free in the DOM: Core & HTML component. (CVE-2026-84125) Privilege escalation in the DOM: Navigation component. (CVE-2026-16371) Privilege escalation in the Application Update component. (CVE-2026-74952) Site isolation issue in the DOM: Navigation component. (CVE-2026-84129) Information disclosure in the Graphics: WebGPU component. (CVE-2026-84130) Privilege escalation due to invalid pointer in the Graphics component. (CVE-2026-84131) Information disclosure in the Networking: HTTP component. (CVE-2026-84132) Site isolation issue in the DOM: Push Subscriptions component. (CVE-2026-84133) Other issue in the Profile Backup component. (CVE-2026-84134) Other issue in the DOM: Navigation component. (CVE-2026-84136) Spoofing issue in the DOM: Core & HTML component. (CVE-2026-84137) Clickjacking issue in the DOM: Events component. (CVE-2026-84139) Site isolation issue in the DOM: Navigation component. (CVE-2026-84140) Integer overflow in the Graphics: ImageLib component. (CVE-2026-84141) Internally found bugs fixed in Thunderbird 155, Thunderbird ESR 153.2 and Thunderbird ESR 140.15. (CVE-2026-84143) Internally found bugs fixed in Thunderbird 155 and Thunderbird ESR 153.2. (CVE-2026-84144) Internally found bugs fixed in Thunderbird 155, Thunderbird ESR 153.2 and Thunderbird ESR 140.15. (CVE-2026-84145)

These are all security issues fixed in the MozillaThunderbird-153.4.0-1.1 package on the GA media of openSUSE Tumbleweed.

This update for MozillaThunderbird fixes the following issues:

Mozilla Thunderbird 153.2:

• fixed: Deleting an Exchange account retained the outgoing server settings
• fixed: Thunderbird upgrade disabled Settings menu for versions before macOS 13
• fixed: Windows jump list menu no longer functioned correctly
• fixed: Security fixes MFSA 2026-88 (bsc#1278001):
• CVE-2026-84639 Uninitialized memory in MIME parsing
• CVE-2026-84640 One byte overflow read in mail parser
• CVE-2026-84641 Information disclosure due to malicious IMAP server response
• CVE-2026-84637 Calendar invitation attachments could launch local executables
• CVE-2026-84642 Allowed UNC hostnames for attachments interpreted as a regular expression
• CVE-2026-75874 Sandbox escape in the Remote Settings Client component
• CVE-2026-84118 Use-after-free in the JavaScript: GC component
• CVE-2026-84119 Sandbox escape due to use-after-free in the DOM: Navigation component
• CVE-2026-84120 Use-after-free in the Audio/Video component
• CVE-2026-84121 Sandbox escape due to use-after-free in the DOM: Security component
• CVE-2026-84122 Use-after-free in the Audio/Video component
• CVE-2026-84123 Privilege escalation due to use-after-free in the Graphics: WebGPU component
• CVE-2026-84124 Use-after-free in the DOM: Core & HTML component
• CVE-2026-84125 Use-after-free in the DOM: Core & HTML component
• CVE-2026-74952 Privilege escalation in the Application Update component
• CVE-2026-84129 Site isolation issue in the DOM: Navigation component
• CVE-2026-84130 Information disclosure in the Graphics: WebGPU component
• CVE-2026-84131 Privilege escalation due to invalid pointer in the Graphics component
• CVE-2026-84132 Information disclosure in the Networking: HTTP component
• CVE-2026-84133 Site isolation issue in the DOM: Push Subscriptions component
• CVE-2026-84134 Other issue in the Profile Backup component
• CVE-2026-84136 Other issue in the DOM: Navigation component
• CVE-2026-84137 Spoofing issue in the DOM: Core & HTML component
• CVE-2026-84139 Clickjacking issue in the DOM: Events component
• CVE-2026-84140 Site isolation issue in the DOM: Navigation component
• CVE-2026-84141 Integer overflow in the Graphics: ImageLib component
• CVE-2026-84143 Internally found bugs fixed in Thunderbird 155, Thunderbird ESR 153.2 and Thunderbird ESR 140.15
• CVE-2026-84144 Internally found bugs fixed in Thunderbird 155 and Thunderbird ESR 153.2
• CVE-2026-84145 Internally found bugs fixed in Thunderbird 155, Thunderbird ESR 153.2 and Thunderbird ESR 140.15

• Mozilla Thunderbird 153.1.1

  • fixed: Thunderbird upgrade disabled composition toolbar
  • fixed: Draft was not preserved when encrypted message send failed
  • fixed: Account Hub prompted for calendar credentials after successful login
  • fixed: Thunderbird crash fixes
  • fixed: Folder compaction showed incorrect disk space recovery estimates
  • fixed: Thunderbird failed to launch GPU process

• Mozilla Thunderbird 153.1

  • fixed: Autoscroll icon was missing directional arrows in scrollable messages
  • fixed: Security fixes MFSA 2026-80 (bsc#1274867):
  • CVE-2026-74934 Site isolation issue in the Graphics: CanvasWebGL component
  • CVE-2026-74935 Privilege escalation in the DOM: Networking component
  • CVE-2026-74936 Use-after-free in the JavaScript: WebAssembly component
  • CVE-2026-74937 Use-after-free in the JavaScript: GC component
  • CVE-2026-74938 Mitigation bypass in the JavaScript: GC component
  • CVE-2026-74939 Privilege escalation in the DOM: Navigation component
  • CVE-2026-74940 Use-after-free in the Graphics: Text component
  • CVE-2026-74941 Privilege escalation in the Graphics:…