CVE-2026-100820 Mozilla Firefox - Privilege Escalation

Mozilla Firefox ESR < 153.4, Firefox < 157, and Firefox ESR < 140.17 contain a privilege escalation caused by a flaw in the Address Bar component, letting attackers escalate privileges, exploit requires unspecified conditions.

CVSS base score 8.8 /10
High
CISA KEV
Not listed
Public exploit
None known
EPSS
0.23% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Privilege Escalation
Impact
Privilege Escalation
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Published
29 September 2026
Updated
15 October 2026
Weakness
CWE-269

Vendor fix

Update to Firefox ESR 153.4, Firefox 157, or Firefox ESR 140.17 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

← All CVEs