Cyber Posture

CVE-2026-2801

High

Published: 24 February 2026

Published
24 February 2026
Modified
13 April 2026
KEV Added
Patch
CVSS Score 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0006 18.4th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Description

Incorrect boundary conditions in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

Likely Mitigating ControlsAI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-754

Requires detection and response to audit logging failures as an unusual or exceptional condition.

addresses: CWE-754

Implements detection of unusual or exceptional conditions followed by safe mode entry, reducing the window for exploitation of unchecked conditions.

addresses: CWE-754

Training ensures users perform required checks for unusual or exceptional conditions as part of contingency roles, limiting attacker leverage from skipped validations.

addresses: CWE-754

IR testing directly validates checks for unusual or exceptional conditions that could indicate security incidents.

addresses: CWE-754

Requires ongoing monitoring of organization-defined metrics and analysis, enabling checks for unusual or exceptional conditions.

addresses: CWE-754

Security testing routinely checks for unusual or exceptional inputs/conditions, identifying missing validation steps that flaw remediation then resolves.

addresses: CWE-754

Requires detection of unusual conditions followed by a controlled transition to the defined failure state.

addresses: CWE-754

MTTF determination forces explicit checks for conditions that precede predictable component failure.

Security SummaryAI

CVE-2026-2801 is a vulnerability involving incorrect boundary conditions in the JavaScript WebAssembly component of Mozilla Firefox and Thunderbird. It affects versions prior to Firefox 148 and Thunderbird 148, where improper handling of boundary checks in WebAssembly processing can lead to issues. The vulnerability is classified under CWE-754 (Improper Check for Unusual or Exceptional Conditions) and carries a CVSS v3.1 base score of 7.5.

Remote attackers can exploit this vulnerability over the network with low complexity, requiring no privileges or user interaction. Successful exploitation results in high-impact denial of service, potentially crashing the affected browser or mail client without compromising confidentiality or integrity.

Mozilla's security advisories (MFSA 2026-13 and MFSA 2026-16) and the associated Bugzilla entry (bug 2009901) confirm the issue was addressed in Firefox 148 and Thunderbird 148. Security practitioners should ensure users update to these patched versions to mitigate the risk.

Details

CWE(s)

Affected Products

mozilla
firefox
≤ 148.0
mozilla
thunderbird
≤ 148.0

MITRE ATT&CK Enterprise TechniquesAI

T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
Why these techniques?

Vulnerability enables remote exploitation of a client application (browser/mail) to cause a crash/DoS with no user interaction or privileges required, directly mapping to application/system exploitation for endpoint denial of service.

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

References