Mitigation bypass in the Storage: Cache API component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable yes

Technical Impact total

Affected Vendors & Products

Vendors Products
Mozilla
  • Firefox
  • Thunderbird

Configuration 1 [-]

OR cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

No data.

References
Link Providers
https://bugzilla.mozilla.org/show_bug.cgi?id=2047853 cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-74959 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-74959 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-74/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-76/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-76/#CVE-2026-74959 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-77/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-78/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-79/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-79/#CVE-2026-74959 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-80/ cve-icon cve-icon
History

Mon, 24 Aug 2026 16:00:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla thunderbird
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
Vendors & Products Mozilla thunderbird

Fri, 21 Aug 2026 20:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-693
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

 ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}

Wed, 19 Aug 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-807
References
Metrics threat_severity

None

 cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

threat_severity

Moderate

Tue, 18 Aug 2026 22:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-284

Tue, 18 Aug 2026 19:00:00 +0000

Type Values Removed Values Added
Description Mitigation bypass in the Storage: Cache API component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. Mitigation bypass in the Storage: Cache API component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
References

Tue, 18 Aug 2026 15:00:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox

Tue, 18 Aug 2026 14:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-284

Tue, 18 Aug 2026 12:45:00 +0000

Type Values Removed Values Added
Description Mitigation bypass in the Storage: Cache API component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1.
Title Mitigation bypass in the Storage: Cache API component
References
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published: 2026-08-18T12:23:31.322Z

Updated: 2026-08-21T20:02:58.368Z

Reserved: 2026-08-17T11:58:20.360Z

Link: CVE-2026-74959

cve-icon Vulnrichment

Updated: 2026-08-21T20:02:52.667Z

cve-icon NVD

Status : Analyzed

Published: 2026-08-18T13:17:33.037

Modified: 2026-08-24T15:52:36.127

Link: CVE-2026-74959

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-08-18T12:23:31Z

Links: CVE-2026-74959 - Bugzilla