CVE-2026-100798

HIGH 8.1CVE-2026-100798 · Published 29/09/2026 · updated 19/10/2026

In short

CVE-2026-100798 is a HIGH (CVSS 8.1) vulnerability affecting firefox (mozilla), thunderbird (mozilla).
Chance of exploitation in the next 30 days (EPSS): 0.19%, higher than 8.9% of all vulnerabilities.
Fix: update to 157.0.0, 153.4.0, 157.0 or later.

Package	Affected versions	Patched versions
firefox mozilla	`≥ 154.0.0, < 157.0.0< 153.4.0`	`157.0.0153.4.0`
thunderbird mozilla	`≥ 154.0, < 157.0< 153.4.0`	`157.0153.4.0`

Description

Cryptography misuse in Storage: Quota Manager component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.

References

bugzilla.mozilla.org/show_bug.cgi · Permissions Required
mozilla.org/security/advisories/mfsa2026-100 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-101 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-103 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-97 · Vendor Advisory

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Package

Affected versions

Patched versions

firefox

mozilla

≥ 154.0.0, < 157.0.0< 153.4.0

157.0.0153.4.0

thunderbird

mozilla

≥ 154.0, < 157.0< 153.4.0

157.0153.4.0

More vulnerabilities in firefox

See all →