Cyber Posture

CVE-2026-2780

Critical

Published: 24 February 2026

Published
24 February 2026
Modified
13 April 2026
KEV Added
Patch
CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0002 5.4th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Description

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

Mitigating Controls (NIST 800-53 r5)AI

prevent

Directly mitigates the privilege escalation vulnerability by requiring timely remediation through patching to Firefox 148, Firefox ESR 140.8, Thunderbird 148, or Thunderbird 140.8.

prevent

Addresses improper privilege management (CWE-269) by enforcing least privilege on the Netmonitor component to limit escalation impact.

prevent

Enforces access control policies to counter unauthorized privilege escalation in the Netmonitor component.

Security SummaryAI

CVE-2026-2780 is a privilege escalation vulnerability in the Netmonitor component affecting Mozilla Firefox, Firefox ESR, and Thunderbird. The issue, associated with CWE-269 (Improper Privilege Management) and lacking specific NVD CWE details, was assigned a critical CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H). It was publicly disclosed on February 24, 2026, and addressed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Remote attackers require no privileges or user interaction to exploit this vulnerability over the network with low complexity. Successful exploitation enables high-impact confidentiality, integrity, and availability violations, allowing attackers to escalate privileges within affected applications, potentially leading to full compromise of the user's system.

Mozilla's security advisories (MFSA 2026-13, 15, 16, and 17) and the associated Bugzilla entry (ID 2007829) confirm the vulnerability's resolution through patches in the specified versions. Security practitioners should prioritize updating to Firefox 148 or later, Firefox ESR 140.8 or later, Thunderbird 148 or later, and Thunderbird 140.8 or later to mitigate this risk.

Details

CWE(s)

Affected Products

mozilla
firefox
≤ 140.8.0 · ≤ 148.0
mozilla
thunderbird
≤ 140.8.0 · ≤ 148.0

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Why these techniques?

CVE describes a remote privilege escalation vulnerability (CWE-269) in a client application that directly enables T1068 Exploitation for Privilege Escalation, leading to full system compromise.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

References