CVE-2026-92049: Vulnerability in Mozilla Firefox
Use-after-free in the Widget: Win32 component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, and Thunderbird 156.
AI Analysis
Technical Summary
This vulnerability involves a use-after-free condition in the Widget: Win32 component of Mozilla Firefox. Use-after-free vulnerabilities occur when a program continues to use a pointer after the memory it points to has been freed, potentially leading to memory corruption. Mozilla fixed this issue in Firefox 156 and Firefox ESR 153.3 as part of their security updates announced on September 15, 2026. The vendor advisory confirms the fix and categorizes the impact as high.
Potential Impact
The vulnerability could allow an attacker to cause memory corruption, which may lead to arbitrary code execution or application crashes. However, there are no reports of active exploitation in the wild. The impact is rated high by Mozilla.
Mitigation Recommendations
Users and administrators should update to Firefox 156 or later, or Firefox ESR 153.3 or later, to remediate this vulnerability. Mozilla has provided an official fix in these versions. No additional mitigation steps are required beyond applying the update.
CVE-2026-92049: Vulnerability in Mozilla Firefox
Description
Use-after-free in the Widget: Win32 component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, and Thunderbird 156.
Affected software
Mozilla
Firefox
Mozilla
Thunderbird
Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves a use-after-free condition in the Widget: Win32 component of Mozilla Firefox. Use-after-free vulnerabilities occur when a program continues to use a pointer after the memory it points to has been freed, potentially leading to memory corruption. Mozilla fixed this issue in Firefox 156 and Firefox ESR 153.3 as part of their security updates announced on September 15, 2026. The vendor advisory confirms the fix and categorizes the impact as high.
Potential Impact
The vulnerability could allow an attacker to cause memory corruption, which may lead to arbitrary code execution or application crashes. However, there are no reports of active exploitation in the wild. The impact is rated high by Mozilla.
Mitigation Recommendations
Users and administrators should update to Firefox 156 or later, or Firefox ESR 153.3 or later, to remediate this vulnerability. Mozilla has provided an official fix in these versions. No additional mitigation steps are required beyond applying the update.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-09-15T12:34:09.926Z
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-90/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-93/","vendor":"Mozilla"}]
Threat ID: 6aa93e6555bf5e2cf5d31006
Added to database: 09/15/2026, 12:47:33 UTC
Last enriched: 09/15/2026, 13:03:17 UTC
Last updated: 09/16/2026, 04:01:24 UTC
Views: 9
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.