CVE-2026-8959

critical

Published 2026-05-27 · Modified 2026-06-03

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CVSS v3

9.6

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

CVSS v4 NEW

—

not yet in upstream

VIR risk

9.6

Description

Important: thunderbird security update

Predictions

Exploit likelihood

96%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

OS impact

SUSE Affected 1 release

Version	Status	Fixed in
—	Affected	—

AlmaLinux Fixed 2 releases

Version	Status	Fixed in
9	Fixed	`thunderbird-140.11.0-1.el9_8.alma.1.ppc64le.rpm`
8	Fixed	`thunderbird-140.11.0-1.el8_10.alma.1.x86_64.rpm`

Debian Fixed 5 releases

Version	Status	Fixed in
trixie	Fixed	`0`
sid	Fixed	`0`
forky	Fixed	`0`
bullseye	Fixed	`0`
bookworm	Fixed	`0`

Red Hat Fixed 2 releases

Version	Status	Fixed in
9	Fixed	—
8	Fixed	—

Application impact

Vendor	Product	Versions	Fixed
mozilla	firefox	`{"endExcluding":"140.11.0"}`	`140.11.0`
mozilla	thunderbird	`{"endExcluding":"140.11"}`	`140.11`

References

CWEs

CWE-20 CWE-119 CWE-693

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.