CVE-2026-5735

critical

Published 2026-04-07 · Modified 2026-05-10

CVSS v3

9.8

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

CVSS v2

—

VIR risk

9.8

Description

Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 149.0.2 and Thunderbird 149.0.2.

Predictions

Exploit likelihood

97%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2026-5735.html

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2026-5735

vendor Authored 2026-05-27

Vendor advisory: security@mozilla.org — https://www.mozilla.org/security/advisories/mfsa2026-25/

OS impact

OS	Version	Status	Fixed in
debian	sid	fixed	`149.0.2-1`
sles		affected

Application impact

Vendor	Product	Versions	Fixed
mozilla	firefox	`{"endExcluding":"149.0.2"}`	`149.0.2`
mozilla	thunderbird	`{"endExcluding":"149.0.2"}`	`149.0.2`

References

CWEs

CWE-787 CWE-125

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