Cyber Posture

CVE-2026-2773

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 0.0003 8.4th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Description

Incorrect boundary conditions in the Web Audio 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 CVE by requiring identification, prioritization, and timely patching of the buffer overflow flaw in affected Firefox and Thunderbird versions.

prevent

Implements memory protections that counter buffer overflow exploits (CWE-119) in the Web Audio component by enforcing non-executable memory and bounds checking.

prevent

Ensures receipt and implementation of Mozilla MFSA advisories specifying patches for this high-severity vulnerability.

Security SummaryAI

CVE-2026-2773 is a high-severity vulnerability stemming from incorrect boundary conditions in the Web Audio component of Mozilla products. 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 a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating critical risk due to its potential for severe impact.

A remote, unauthenticated attacker can exploit this vulnerability over the network with low complexity and no user interaction required. Successful exploitation enables high-impact compromise of confidentiality, integrity, and availability, likely allowing arbitrary code execution within the browser's rendering process via malicious web content, such as audio files or Web Audio API usage.

Mozilla has addressed the vulnerability in the specified fixed releases: Firefox 148, Firefox ESR 115.33 and 140.8, Thunderbird 148 and 140.8. Security advisories (MFSA 2026-13 through 16) and the Bugzilla entry (bug 2014832) detail the patches and recommend immediate upgrading to mitigate exposure.

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?

Memory corruption RCE in browser rendering process via malicious web content (Web Audio) directly enables drive-by site exploitation and client application exploitation for code execution.

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

References