Memory Corruption Vulnerabilities in Firefox and Firefox ESR
CVE-2026-84143

Currently unrated

Key Information:

Vendor

Mozilla
Status
Firefox
Vendor
CVE Published:
1 September 2026

What is CVE-2026-84143?

Multiple memory corruption vulnerabilities were discovered internally in Firefox versions 154, ESR 153.1, and ESR 140.14. These issues could potentially lead to unauthorized access or manipulation of data within the browser, raising significant security concerns. If exploited, these vulnerabilities pose a risk to user data integrity and browser performance. Mozilla has addressed these vulnerabilities in the latest updates, specifically Firefox 155, ESR 140.15, and ESR 153.2, ensuring enhanced security measures are in place.

Affected Version(s)

Firefox 140.15

Firefox 153.2

Firefox 155

References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=2048793%2...
https://bugzilla.mozilla.org/buglist.cgi?bug_id=2054631%2...
https://bugzilla.mozilla.org/show_bug.cgi?id=2057108

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Jan de Mooij, Tom Ritter and the Mozilla Fuzzing Team
.