CVE-2026-100766: Vulnerability in Mozilla Firefox
Information disclosure in the Networking: JAR 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 information disclosure within the Networking: JAR component of Mozilla Firefox. It was reported and fixed by Mozilla in multiple Firefox ESR and standard releases. The Mozilla Foundation Security Advisory 2026-100 lists this as one of several high-impact vulnerabilities resolved in Firefox ESR 153.4 and Firefox 157, among others. The advisory confirms the fix and provides references to the relevant bug tracking entry (Bug 2061526).
Potential Impact
The vulnerability could lead to unauthorized information disclosure through the Networking: JAR component. Mozilla rates the impact as high, indicating significant risk if exploited. However, there are no reports of active exploitation in the wild at this time.
Mitigation Recommendations
Users and administrators should update to Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, Firefox ESR 140.17, or later versions where this vulnerability is fixed. Applying these official updates fully mitigates the risk associated with this vulnerability.
CVE-2026-100766: Vulnerability in Mozilla Firefox
Description
Information disclosure in the Networking: JAR 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 4.3medium
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 information disclosure within the Networking: JAR component of Mozilla Firefox. It was reported and fixed by Mozilla in multiple Firefox ESR and standard releases. The Mozilla Foundation Security Advisory 2026-100 lists this as one of several high-impact vulnerabilities resolved in Firefox ESR 153.4 and Firefox 157, among others. The advisory confirms the fix and provides references to the relevant bug tracking entry (Bug 2061526).
Potential Impact
The vulnerability could lead to unauthorized information disclosure through the Networking: JAR component. Mozilla rates the impact as high, indicating significant risk if exploited. However, there are no reports of active exploitation in the wild at this time.
Mitigation Recommendations
Users and administrators should update to Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, Firefox ESR 140.17, or later versions where this vulnerability is fixed. Applying these official updates fully mitigates the risk associated with this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-09-26T19:15:22.826Z
- 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: 6abbb3edf7a7c5410664096a
Added to database: 09/29/2026, 12:49:49 UTC
Last enriched: 09/29/2026, 13:33:37 UTC
Last updated: 09/29/2026, 18:20:12 UTC
Views: 3
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