8.8 High

CVE-2026-118011 Frame poisoning in the CSS Parsing and Computation component

Description

Frame poisoning in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.

CVSS 3.1 detail

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

Exploitable remotely over the network, without an account and if a user takes an action; an attacker can seriously compromise confidentiality, integrity or availability.

Attack vector: Network
Attack complexity: Low
Privileges required: None
Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Affected products and versions

Product	Affected versions	Fixed in
Firefox 159	earliest → < 159	159
Thunderbird 159	earliest → < 159	159

References

bugzilla.mozilla.org bugzilla.mozilla.org
www.mozilla.org www.mozilla.org
www.mozilla.org www.mozilla.org

Timeline

Published October 27, 2026
Last modified November 5, 2026

The 2221 CVEs of Firefox →

CVE-2026-120572 Incorrect boundary conditions in the Layout: Block and Inline component 8.8 High CVE-2026-118027 Frame poisoning in the Layout component 9.1 Critical CVE-2026-118024 Use-after-free in the Graphics: Text component 8.8 High CVE-2026-118026 Invalid pointer in the JavaScript: GC component 8.8 High

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