CVE-2026-109778CWE-269privilege-escalation

CVE-2026-109778

High · published October 13, 2026

CVSS v3.1
8.8
EPSS
0%
Percentile
19.4
In the wild
Unconfirmed
What it is

Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

The record
Technical detail
CVSS v3.1
8.8 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00280 · 19.4th percentile
Weakness
CWE-269 · Improper Privilege Management
Published
2026-10-13T17:17Z
References (5)
https://bugzilla.mozilla.org/show_bug.cgi?id=2070547 · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-106/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-108/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-109/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-110/ · [email protected]
EPSS history
Timeline
  • 15 OCT 03:28Z
    EPSS moved — → 0%
    epss
  • 13 OCT 12:29Z
    Privilege escalation in the WebExtensions component
    cvelistv5
  • 13 OCT 12:29Z
    Privilege escalation in the WebExtensions component
    cvelistv5