CVE-2026-74959: Vulnerability in Mozilla Firefox
CVE-2026-74959 is a mitigation bypass vulnerability in the Storage: Cache API component of Mozilla Firefox. It was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. The vulnerability has a high CVSS score of 9.1, indicating critical severity. The vendor advisory confirms the fix is available in these versions. No known exploits in the wild have been reported.
AI Analysis
Technical Summary
This vulnerability involves a mitigation bypass in the Storage: Cache API component of Mozilla Firefox. It was reported by David Bors at Snyk Security Labs and is tracked as CVE-2026-74959. The issue was addressed and fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. The CVSS v3.1 base score is 9.1, reflecting a critical impact with network attack vector, low attack complexity, no privileges or user interaction required, and high confidentiality and integrity impact. The vendor advisory explicitly states the fix is included in the specified versions.
Potential Impact
The vulnerability allows an attacker to bypass mitigation controls in the Storage: Cache API component, potentially compromising confidentiality and integrity of data handled by Firefox. The CVSS score of 9.1 indicates a critical impact, meaning exploitation could lead to significant unauthorized data access or modification. However, there are no known exploits in the wild at this time.
Mitigation Recommendations
A fix is available and users should upgrade to Firefox 154, Firefox ESR 140.14, or Firefox ESR 153.1 or later. Applying these updates will remediate the vulnerability. No additional mitigation actions are required beyond applying the official patches.
CVE-2026-74959: Vulnerability in Mozilla Firefox
Description
CVE-2026-74959 is a mitigation bypass vulnerability in the Storage: Cache API component of Mozilla Firefox. It was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. The vulnerability has a high CVSS score of 9.1, indicating critical severity. The vendor advisory confirms the fix is available in these versions. No known exploits in the wild have been reported.
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
This vulnerability involves a mitigation bypass in the Storage: Cache API component of Mozilla Firefox. It was reported by David Bors at Snyk Security Labs and is tracked as CVE-2026-74959. The issue was addressed and fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. The CVSS v3.1 base score is 9.1, reflecting a critical impact with network attack vector, low attack complexity, no privileges or user interaction required, and high confidentiality and integrity impact. The vendor advisory explicitly states the fix is included in the specified versions.
Potential Impact
The vulnerability allows an attacker to bypass mitigation controls in the Storage: Cache API component, potentially compromising confidentiality and integrity of data handled by Firefox. The CVSS score of 9.1 indicates a critical impact, meaning exploitation could lead to significant unauthorized data access or modification. However, there are no known exploits in the wild at this time.
Mitigation Recommendations
A fix is available and users should upgrade to Firefox 154, Firefox ESR 140.14, or Firefox ESR 153.1 or later. Applying these updates will remediate the vulnerability. No additional mitigation actions are required beyond applying the official patches.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-08-17T11:58:20.360Z
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-74/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-76/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-77/","vendor":"Mozilla"}]
Threat ID: 6a845507c6e8be03323673ed
Added to database: 08/18/2026, 12:50:15 UTC
Last enriched: 09/11/2026, 22:02:18 UTC
Last updated: 10/02/2026, 02:46:06 UTC
Views: 32
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