SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-12311

Information disclosure, sandbox escape in the Security: Process Sandboxing component.

MEDIUM 4.7EPSS 0.18%

Does this matter?

Lower severity and a low EPSS score (0.18%). Track it; it rarely justifies an emergency change on its own.

Description

Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

CVSS 3.1
4.7 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N
EPSS
0.18% probability · 8th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-200, CWE-688
Affected
mozilla/firefox · mozilla/thunderbird
Source
security@mozilla.org
EPSS trend
0%3%5%26 October 2026: 0.18%26 October 202626 October 2026

EPSS 0.2% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

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