SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2026-109770

This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

MEDIUM 6.1EPSS 0.19%

Does this matter?

Lower severity and a low EPSS score (0.19%). Track it; it rarely justifies an emergency change on its own.

Description

Spoofing issue in the DOM: Web Serial component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

CVSS 3.1
6.1 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS
0.19% probability · 8th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-20
Source
security@mozilla.org
EPSS trend
0%3%5%14 October 2026: 0.19%26 October 2026: 0.19%14 October 202626 October 2026

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