Linux · Security advisory · September 13, 2026

RHSA-2026:65158: thunderbird security update

RHSA-2026:65158, released September 13, 2026, fixes 23 CVEs in thunderbird (version 0:140.14.0-1.el9_8). None of them is reported as exploited. Patch Radar priority: Urgent.

Urgent
CVEs closed
23
4 rated Critical
Exploited
0
None reported
Exploitation more likely
0
Vendor assessment
Highest EPSS
0.0072
53rd percentile

Priority of the 23 CVEs

Patch now 0 Urgent 4 High 19 Routine 0

Fixed package versions

ProductReleaseFixed in
thunderbirdRHEL 90:140.14.0-1.el9_8

CVEs this fix closes

PriorityCVETitleImpactCVSSEPSSExploitation
Urgent CVE-2026-74940 Use-after-free in the Graphics: Text component 9.8 0.0061 None reported
Urgent CVE-2026-74943 Use-after-free in the Graphics: ImageLib component 9.8 0.0061 None reported
Urgent CVE-2026-74944 Use-after-free in the DOM: Core & HTML component 9.8 0.0059 None reported
Urgent CVE-2026-74959 Mitigation bypass in the Storage: Cache API component 9.1 0.0048 None reported
High CVE-2026-74987 Internally found bugs fixed in Thunderbird ESR 140.14, Thunderbird ESR 153.1 and Thunderbird 154 9.8 0.0072 None reported
High CVE-2026-74990 Internally found bugs fixed in Thunderbird ESR 140.14, Thunderbird ESR 153.1 and Thunderbird 154 9.8 0.0072 None reported
High CVE-2026-74946 Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component 8.8 0.0050 None reported
High CVE-2026-74949 Privilege escalation due to use-after-free in the Graphics: Canvas2D component 8.8 0.0047 None reported
High CVE-2026-74935 Privilege escalation in the DOM: Networking component 8.8 0.0045 None reported
High CVE-2026-74939 Privilege escalation in the DOM: Navigation component 8.8 0.0045 None reported
High CVE-2026-74942 Privilege escalation in the Remote Settings Client component 8.8 0.0045 None reported
High CVE-2026-74965 Privilege escalation in the Shell Integration component 8.8 0.0044 None reported
High CVE-2026-74945 Information disclosure in the Graphics: Text component 7.5 0.0044 None reported
High CVE-2026-74957 Mitigation bypass in the Safe Browsing component 8.1 0.0043 None reported
High CVE-2026-74976 JIT miscompilation in the JavaScript Engine: JIT component 7.5 0.0042 None reported
High CVE-2026-74971 Information disclosure in the DOM: UI Events & Focus Handling component 7.5 0.0035 None reported
High CVE-2026-74972 Information disclosure in the DOM: Push Subscriptions component 7.5 0.0035 None reported
High CVE-2026-74960 Site isolation issue in the WebExtensions component 8.1 0.0022 None reported
High CVE-2026-74962 Site isolation issue in the Networking: Cookies component 8.1 0.0022 None reported
High CVE-2026-74973 Race condition, use-after-free in the Graphics component 7.5 0.0022 None reported
High CVE-2026-74934 Site isolation issue in the Graphics: CanvasWebGL component 7.5 0.0021 None reported
High CVE-2026-74974 Same-origin policy bypass in the Graphics: ImageLib component 7.5 0.0017 None reported
High CVE-2026-74963 Same-origin policy bypass in the Networking: Cookies component 7.5 0.0017 None reported
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