SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2026-109704

Privilege escalation in the Application Update component.

HIGH 8.8EPSS 0.41%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.41%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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

CVSS 3.1
8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS
0.41% probability · 35th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-269
Source
security@mozilla.org
EPSS trend
0%3%5%14 October 2026: 0.19%26 October 2026: 0.41%14 October 202626 October 2026

EPSS moved from 0.2% on 14 October 2026 to 0.4% on 26 October 2026.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.