Cyber Posture

CVE-2026-2788

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 7.0th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Description

Incorrect boundary conditions in the Audio/Video: GMP component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Mitigating Controls (NIST 800-53 r5)AI

prevent

Directly addresses the vulnerability by requiring timely identification, testing, and installation of patches for the GMP buffer overflow flaw in affected Firefox and Thunderbird versions.

prevent

Mitigates buffer overflow exploitation through memory protections like ASLR, DEP, and stack canaries, reducing the likelihood of arbitrary code execution from malicious media.

prevent

Enforces process isolation for the GMP media decoding component, containing potential exploits to prevent full system compromise.

Security SummaryAI

CVE-2026-2788 is a high-severity vulnerability stemming from incorrect boundary conditions in the Audio/Video: GMP (Gonk Media Plugin) component used by Mozilla products for media decoding. It affects Firefox versions prior to 148, Firefox ESR prior to 115.33 and 140.8, Thunderbird prior to 148 and 140.8. The issue is classified under CWE-119 (improper restriction of operations within the bounds of a memory buffer) with an additional NVD-CWE-noinfo mapping, earning a CVSS v3.1 base score of 9.8.

The vulnerability enables remote attackers to exploit it over the network with low complexity, requiring no privileges or user interaction. Successful exploitation grants high-impact confidentiality, integrity, and availability violations, potentially allowing arbitrary code execution, data theft, or system compromise when processing malicious audio or video content via the GMP component.

Mozilla security advisories (MFSA 2026-13 through 2026-16) and the associated Bugzilla entry (2014824) confirm the issue was addressed in the listed fixed releases. Security practitioners should prioritize updating affected Firefox and Thunderbird installations to mitigate the risk, as no workarounds are detailed in the provided references.

Details

CWE(s)

Affected Products

mozilla
firefox
≤ 115.33.0 · ≤ 148.0 · 128.0 — 140.8.0
mozilla
thunderbird
≤ 140.8.0 · ≤ 148.0

MITRE ATT&CK Enterprise TechniquesAI

T1189 Drive-by Compromise Initial Access
Adversaries may gain access to a system through a user visiting a website over the normal course of browsing.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
Why these techniques?

Buffer overflow in client-side media decoder (GMP) enables RCE on Firefox/Thunderbird via malicious audio/video with no user interaction, directly mapping to drive-by compromise and client exploitation techniques.

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

References