CVE-2026-100757: Vulnerability in Mozilla Firefox
Use-after-free in the Widget component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
AI Analysis
Technical Summary
This vulnerability involves a use-after-free condition in the Widget component of Mozilla Firefox, which could potentially lead to memory corruption or other unintended behavior. Mozilla has addressed this issue by releasing fixes in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. The advisory is part of a broader set of security fixes announced on September 29, 2026, with this specific issue reported by Mohamed Mbarek and tracked under Bug 2049352.
Potential Impact
The vulnerability is rated as high impact by Mozilla, indicating that successful exploitation could lead to significant security consequences such as memory corruption. However, there are no reports of active exploitation in the wild at this time.
Mitigation Recommendations
Mozilla has released official fixes for this vulnerability in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. Users and administrators should update to these versions or later to remediate the issue. No additional mitigation is required beyond applying these updates.
CVE-2026-100757: Vulnerability in Mozilla Firefox
Description
Use-after-free in the Widget component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
CVSS v3.1
Score 8.8high
Affected software
Mozilla
Firefox
pkg:github/mozilla/firefoxRun 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
This vulnerability involves a use-after-free condition in the Widget component of Mozilla Firefox, which could potentially lead to memory corruption or other unintended behavior. Mozilla has addressed this issue by releasing fixes in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. The advisory is part of a broader set of security fixes announced on September 29, 2026, with this specific issue reported by Mohamed Mbarek and tracked under Bug 2049352.
Potential Impact
The vulnerability is rated as high impact by Mozilla, indicating that successful exploitation could lead to significant security consequences such as memory corruption. However, there are no reports of active exploitation in the wild at this time.
Mitigation Recommendations
Mozilla has released official fixes for this vulnerability in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. Users and administrators should update to these versions or later to remediate the issue. No additional mitigation is required beyond applying these updates.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-09-26T19:15:14.718Z
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-100/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-97/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-98/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-99/","vendor":"Mozilla"}]
Threat ID: 6abbb3ebf7a7c5410664093b
Added to database: 09/29/2026, 12:49:47 UTC
Last enriched: 09/29/2026, 13:48:10 UTC
Last updated: 09/29/2026, 18:20:12 UTC
Views: 2
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