CVE-2026-74959
Medium
Elevated severity or exploit probability.
CVSS base
9.1
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS — probability of exploitation (30 days)
0.3%
27.8th percentile
CISA KEV
Not listed
Weakness / dates
CWE-693
Published 2026-08-18 · modified 2026-08-24
CVSS breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
| Attack Vector | N | Network |
| Attack Complexity | L | Low |
| Privileges Required | N | None |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | H | High |
| Integrity | H | High |
| Availability | N | None |
Timeline
- 2026-08-18 — Published (NVD)
- 2026-08-24 — Last modified (NVD)
Description
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.
Affected
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2047853
- https://www.mozilla.org/security/advisories/mfsa2026-74/
- https://www.mozilla.org/security/advisories/mfsa2026-76/
- https://www.mozilla.org/security/advisories/mfsa2026-77/
- https://www.mozilla.org/security/advisories/mfsa2026-78/
- https://www.mozilla.org/security/advisories/mfsa2026-79/
- https://www.mozilla.org/security/advisories/mfsa2026-80/