CVE-2026-74938: Vulnerability in Mozilla Firefox
Mitigation bypass in the JavaScript: GC component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
AI Analysis
Technical Summary
CVE-2026-74938 is a mitigation bypass vulnerability affecting the JavaScript GC component in Mozilla Firefox. The flaw could allow an attacker to bypass security mitigations related to garbage collection in JavaScript execution. This vulnerability was fixed in Firefox 154 and Firefox ESR 153.1 as part of a broader security update addressing multiple high-impact issues. The vendor advisory confirms the fix and classifies the impact as high. No evidence of exploitation in the wild has been reported.
Potential Impact
The vulnerability allows bypassing mitigation mechanisms in the JavaScript GC component, which could potentially lead to security issues such as memory corruption or privilege escalation. The vendor rates the impact as high, indicating a significant security risk if exploited. However, no active exploitation has been observed in the wild.
Mitigation Recommendations
Mozilla has released official fixes for this vulnerability in Firefox 154 and Firefox ESR 153.1. Users and administrators should update to these versions or later to remediate the vulnerability. Since the vulnerability is fixed in these versions, no additional mitigation steps are required beyond applying the official update.
CVE-2026-74938: Vulnerability in Mozilla Firefox
Description
Mitigation bypass in the JavaScript: GC component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
CVSS v3.1
Score 9.1critical
Affected software
Mozilla
Firefox
Mozilla
Thunderbird
pkg:github/mozilla/firefox-esrRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-74938 is a mitigation bypass vulnerability affecting the JavaScript GC component in Mozilla Firefox. The flaw could allow an attacker to bypass security mitigations related to garbage collection in JavaScript execution. This vulnerability was fixed in Firefox 154 and Firefox ESR 153.1 as part of a broader security update addressing multiple high-impact issues. The vendor advisory confirms the fix and classifies the impact as high. No evidence of exploitation in the wild has been reported.
Potential Impact
The vulnerability allows bypassing mitigation mechanisms in the JavaScript GC component, which could potentially lead to security issues such as memory corruption or privilege escalation. The vendor rates the impact as high, indicating a significant security risk if exploited. However, no active exploitation has been observed in the wild.
Mitigation Recommendations
Mozilla has released official fixes for this vulnerability in Firefox 154 and Firefox ESR 153.1. Users and administrators should update to these versions or later to remediate the vulnerability. Since the vulnerability is fixed in these versions, no additional mitigation steps are required beyond applying the official update.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-08-17T11:57:33.871Z
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-74/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-77/","vendor":"Mozilla"}]
Threat ID: 6a845502c6e8be033236739f
Added to database: 08/18/2026, 12:50:10 UTC
Last enriched: 08/18/2026, 14:21:51 UTC
Last updated: 10/02/2026, 09:47:13 UTC
Views: 28
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