Use-after-free in the Widget component. (CVE-2026-100757)
CVE-2026-100757 is a use-after-free vulnerability in the Widget component of Firefox. This security flaw allows for potential high impact on confidentiality, integrity, and availability. The vulnerability has been fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. No known exploits are reported in the wild at this time.
AI Analysis
Technical Summary
CVE-2026-100757 is a use-after-free vulnerability affecting the Widget component in Firefox. This type of vulnerability occurs when a program continues to use a pointer after it has been freed, potentially leading to arbitrary code execution or application crashes. The issue was reported by Mohamed Mbarek and has been addressed by Mozilla in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. The CVSS v3.1 base score is 8.8, indicating a high severity with network attack vector, low attack complexity, no privileges required, user interaction required, and impacts on confidentiality, integrity, and availability.
Potential Impact
Successful exploitation of this use-after-free vulnerability could allow an attacker to execute arbitrary code, cause application crashes, or otherwise compromise the confidentiality, integrity, and availability of the affected Firefox browser. The CVSS score of 8.8 reflects a high impact on security.
Mitigation Recommendations
This vulnerability has been fixed 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 steps are required as the fix is officially provided by Mozilla.
Use-after-free in the Widget component. (CVE-2026-100757)
Description
CVE-2026-100757 is a use-after-free vulnerability in the Widget component of Firefox. This security flaw allows for potential high impact on confidentiality, integrity, and availability. The vulnerability has been fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. No known exploits are reported in the wild at this time.
CVSS v3.1
Score 8.8high
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-100757 is a use-after-free vulnerability affecting the Widget component in Firefox. This type of vulnerability occurs when a program continues to use a pointer after it has been freed, potentially leading to arbitrary code execution or application crashes. The issue was reported by Mohamed Mbarek and has been addressed by Mozilla in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. The CVSS v3.1 base score is 8.8, indicating a high severity with network attack vector, low attack complexity, no privileges required, user interaction required, and impacts on confidentiality, integrity, and availability.
Potential Impact
Successful exploitation of this use-after-free vulnerability could allow an attacker to execute arbitrary code, cause application crashes, or otherwise compromise the confidentiality, integrity, and availability of the affected Firefox browser. The CVSS score of 8.8 reflects a high impact on security.
Mitigation Recommendations
This vulnerability has been fixed 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 steps are required as the fix is officially provided by Mozilla.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-q9fp-c34q-3gpp
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-100757"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6abc27cb680226ef6846f8a5
Added to database: 09/29/2026, 21:04:11 UTC
Last enriched: 09/29/2026, 21:21:02 UTC
Last updated: 09/30/2026, 03:38:53 UTC
Views: 3
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.