Red Hat Security Advisory: thunderbird security update

Fixed packages 3

Vulnerabilities 29

• Critical 9.6
  CVE-2026-12294

  Sandbox escape in the DOM: Workers component

  Sandbox escape in the DOM: Workers component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Critical 9.6
  CVE-2026-12295 Public exploit

  Sandbox escape in the DOM: Navigation component

  Sandbox escape in the DOM: Navigation component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Critical 9.6
  CVE-2026-12296

  Sandbox escape in the Security: Process Sandboxing component

  Sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Critical 9.6
  CVE-2026-12297

  Sandbox escape due to incorrect boundary conditions in the Networking component

  Sandbox escape due to incorrect boundary conditions in the Networking component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Critical 9.1
  CVE-2026-12304

  Same-origin policy bypass in the Networking: Cookies component

  Same-origin policy bypass in the Networking: Cookies component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Critical 9.1
  CVE-2026-12315

  Mitigation bypass in the DOM: Security component

  Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• High 8.8
  CVE-2026-12289

  Privilege escalation in the Graphics: WebRender component

  Privilege escalation in the Graphics: WebRender component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• High 8.8
  CVE-2026-12291

  Use-after-free in the Networking: HTTP component

  Use-after-free in the Networking: HTTP component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• High 8.1
  CVE-2026-12290

  Memory safety bug fixed in Thunderbird 152

  Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• High 8.1
  CVE-2026-12292

  Incorrect boundary conditions in the Web Audio component

  Incorrect boundary conditions in the Web Audio component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• High 8.1
  CVE-2026-12327

  Memory safety bugs fixed in Firefox ESR 140.12, Thunderbird ESR 140.12, Firefox 152 and Thunderbird 152

  Memory safety bugs present in Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151 and Thunderbird 151. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary …

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• High 8.1
  CVE-2026-12328

  Memory safety bugs fixed in Firefox ESR 115.37, Firefox ESR 140.12, Thunderbird ESR 140.12, Firefox 152 and Thunderbird 152

  Memory safety bugs present in Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151 and Thunderbird 151. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploit…

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• High 7.5
  CVE-2026-12305

  Memory safety bug fixed in Thunderbird 152

  Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• High 7.5
  CVE-2026-12310

  Memory safety bug fixed in Thunderbird 152

  Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• High 7.5
  CVE-2026-12312

  Memory safety bug fixed in Thunderbird 152

  Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• High 7.5
  CVE-2026-12314

  Memory safety bug fixed in Thunderbird 152

  Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• High 7.3
  CVE-2026-12324

  Incorrect boundary conditions in the Graphics: CanvasWebGL component

  Incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Medium 6.5
  CVE-2026-12302

  Mitigation bypass in the DOM: Security component

  Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Medium 6.5
  CVE-2026-12309

  Memory safety bug fixed in Thunderbird 152

  Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Medium 6.5
  CVE-2026-12325

  Denial-of-service in the Graphics: ImageLib component

  Denial-of-service in the Graphics: ImageLib component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Medium 5.4
  CVE-2026-12298

  Memory safety bug fixed in Thunderbird 152

  Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Medium 5.4
  CVE-2026-12299

  JIT miscompilation in the DOM: Core & HTML component

  JIT miscompilation in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Medium 5.4
  CVE-2026-12330

  Incorrect boundary conditions in the Internationalization component

  Incorrect boundary conditions in the Internationalization component. This vulnerability was fixed in Firefox ESR 140.12, Firefox ESR 115.37, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Medium 5.3
  CVE-2026-12306

  Memory safety bug fixed in Thunderbird 152

  Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Medium 5.3
  CVE-2026-12307

  Memory safety bug fixed in Thunderbird 152

  Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Medium 5.3
  CVE-2026-12308

  Memory safety bug fixed in Thunderbird 152

  Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Medium 5.3
  CVE-2026-12329

  Memory safety bug fixed in Thunderbird ESR 140.12

  Memory safety bug fixed in Thunderbird ESR 140.12. This vulnerability was fixed in Firefox ESR 140.12 and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Medium 4.7
  CVE-2026-12311

  Information disclosure, sandbox escape in the Security: Process Sandboxing component

  Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026
• Medium 4.7
  CVE-2026-12313

  Information disclosure, sandbox escape in the Security: Process Sandboxing component

  Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

  Mozilla Firefox Thunderbird thunderbird Browsers Debian Ubuntu Wolfi
  Jun 16, 2026

References

• article
  https://access.redhat.com/security/updates/classification/#important
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489207
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489208
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489209
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489210
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489211
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489212
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489214
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489215
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489217
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489218
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489220
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489221
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489223
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489224
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489225
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489226
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489229
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489231
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489232
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489233
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489234
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489235
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489236
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489237
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489239
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489240
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489243
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489244
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2489248
• advisory
  https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_38751.json
• report
  https://access.redhat.com/security/cve/CVE-2026-12289
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-12289
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-12289
• article
  https://www.mozilla.org/security/advisories/mfsa2026-58/#CVE-2026-12289
• article
  https://www.mozilla.org/security/advisories/mfsa2026-61/#CVE-2026-12289
• report
  https://access.redhat.com/security/cve/CVE-2026-12290
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-12290
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-12290