SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2026-84138

Denial-of-service in the PDF Viewer component.

MEDIUM 6.5EPSS 0.20%

Does this matter?

Lower severity and a low EPSS score (0.20%). Track it; it rarely justifies an emergency change on its own.

Description

Denial-of-service in the PDF Viewer component. This vulnerability was fixed in Firefox 155 and Thunderbird 155.

CVSS 3.1
6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS
0.20% probability · 11th percentile
CISA KEV
Not listed
Weakness
CWE-400
Affected
mozilla/firefox · mozilla/thunderbird
Source
security@mozilla.org

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.