Cyber Posture

CVE-2026-2802

Medium

Published: 24 February 2026

Published
24 February 2026
Modified
13 April 2026
KEV Added
Patch
CVSS Score 4.2 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
EPSS Score 0.0003 8.8th percentile
Risk Priority 8 60% EPSS · 20% KEV · 20% CVSS

Description

Race condition in the JavaScript: GC 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-362

Accurate timestamps from internal clocks enable detection of race conditions by providing reliable event ordering in audit logs.

addresses: CWE-362

Coordination of concurrent security activities reduces the probability that shared resources will be accessed simultaneously without proper synchronization.

Security SummaryAI

CVE-2026-2802 is a race condition vulnerability (CWE-362) in the JavaScript Garbage Collector (GC) component of Mozilla Firefox and Thunderbird. It affects versions prior to Firefox 148 and Thunderbird 148, where the flaw allows concurrent access issues during garbage collection operations in JavaScript execution. The vulnerability has a CVSS v3.1 base score of 4.2 (AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N), rated as Medium severity due to its network accessibility but high attack complexity and requirement for user interaction.

An unauthenticated remote attacker can exploit this vulnerability by crafting malicious web content that triggers the race condition in the JavaScript GC, typically requiring the user to interact with a malicious webpage or link. Successful exploitation could result in limited impacts, such as low-level disclosure of sensitive information or minor modification of data, without affecting availability or escalating privileges.

Mozilla's security advisories (MFSA 2026-13 and MFSA 2026-16) and the associated Bugzilla entry (bug 2011069) confirm the issue was addressed in Firefox 148 and Thunderbird 148. Security practitioners should prioritize updating affected browsers to these patched versions to mitigate the risk, as no workarounds are detailed in the provided references.

Details

CWE(s)

Affected Products

mozilla
firefox
≤ 148.0
mozilla
thunderbird
≤ 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.
T1204.001 Malicious Link Execution
An adversary may rely upon a user clicking a malicious link in order to gain execution.
Why these techniques?

Vulnerability enables drive-by exploitation of browser via malicious web content requiring user interaction (T1189, T1204.001) and direct client-side exploitation for limited info disclosure/data modification (T1203).

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

References