CVE-2026-92064

HIGH 8.8CVE-2026-92064 · Published 15/09/2026 · updated 05/10/2026

In short

CVE-2026-92064 is a HIGH (CVSS 8.8) vulnerability affecting firefox (mozilla), thunderbird (mozilla).
Chance of exploitation in the next 30 days (EPSS): 0.10%, higher than 0.97% of all vulnerabilities.
Fix: update to 156.0.0, 153.3.0, 156.0 or later.

Package	Affected versions	Patched versions
firefox mozilla	`≥ 154.0.0, < 156.0.0< 153.3.0`	`156.0.0153.3.0`
thunderbird mozilla	`≥ 154.0, < 156.0< 153.3.0`	`156.0153.3.0`

Description

Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.

References

bugzilla.mozilla.org/show_bug.cgi · Permissions Required
mozilla.org/security/advisories/mfsa2026-90 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-93 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-94 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-96 · Vendor Advisory

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Package

Affected versions

Patched versions

firefox

mozilla

≥ 154.0.0, < 156.0.0< 153.3.0

156.0.0153.3.0

thunderbird

mozilla

≥ 154.0, < 156.0< 153.3.0

156.0153.3.0

More vulnerabilities in firefox

See all →