CVE-2026-2780

CRITICAL

Firefox <148 & ESR <140.8 - Privilege Escalation

Title source: llm

Description

Privilege escalation in the Netmonitor component. This vulnerability affects Firefox < 148, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.

References (5)

[Issue Tracking] https://bugzilla.mozilla.org/show_bug.cgi?id=2007829

[Vendor Advisory] https://www.mozilla.org/security/advisories/mfsa2026-13/

[Vendor Advisory] https://www.mozilla.org/security/advisories/mfsa2026-15/

[Vendor Advisory] https://www.mozilla.org/security/advisories/mfsa2026-16/

[Vendor Advisory] https://www.mozilla.org/security/advisories/mfsa2026-17/

Scores

CVSS v3 9.8

EPSS 0.0004

EPSS Percentile 13.1%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Classification

CWE

CWE-269

Status published

Affected Products (4)

mozilla/firefox < 140.8.0

mozilla/firefox < 148.0

mozilla/thunderbird < 140.8.0

mozilla/thunderbird < 148.0

Timeline

Published Feb 24, 2026

Tracked Since Feb 24, 2026