CVE-2026-6753

HIGH 7.3CVE-2026-6753 · Published 21/04/2026 · updated 26/10/2026

In short

CVE-2026-6753 is a HIGH (CVSS 7.3) vulnerability affecting firefox (mozilla), thunderbird (mozilla).
Chance of exploitation in the next 30 days (EPSS): 0.31%, higher than 23.5% of all vulnerabilities.
Fix: update to 140.10.0, 150.0 or later.

Package	Affected versions	Patched versions
firefox mozilla	`< 140.10.0< 150.0`	`140.10.0150.0`
thunderbird mozilla	`≥ 140.0, < 140.10.0`	`140.10.0`

Description

Incorrect boundary conditions in the WebRTC component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

References

bugzilla.mozilla.org/show_bug.cgi · Permissions Required
mozilla.org/security/advisories/mfsa2026-30 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-32 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-33 · Vendor Advisory
mozilla.org/security/advisories/mfsa2026-34 · Vendor Advisory
access.redhat.com/errata/RHSA-2026:10757
access.redhat.com/errata/RHSA-2026:10766
access.redhat.com/errata/RHSA-2026:10767
access.redhat.com/errata/RHSA-2026:12285
access.redhat.com/errata/RHSA-2026:13537
access.redhat.com/errata/RHSA-2026:15892
access.redhat.com/errata/RHSA-2026:17477
access.redhat.com/errata/RHSA-2026:17687

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