CVE-2026-74954CWE-203

CVE-2026-74954

High · published August 18, 2026

CVSS v3.1

7.5

EPSS

Percentile

37.1

In the wild

Unconfirmed

What it is

Information disclosure due to side-channel in the Storage: Cache API component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.

The record

Technical detail

CVSS v3.1: 7.5 · HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS v4.0: Not supplied
EPSS: 0.00439 · 37.1th percentile
Weakness: CWE-203 · Observable Discrepancy
Published: 2026-08-18T17:17Z

Affected products (4)

Product	Versions	Fixed in
mozilla/firefox	< 153.1.0	153.1.0
mozilla/firefox	< 154.0.0	154.0.0
mozilla/thunderbird	< 153.1.0	153.1.0
mozilla/thunderbird	< 154.0	154.0

References (5)

https://bugzilla.mozilla.org/show_bug.cgi?id=2025732 · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-74/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-77/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-78/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-80/ · [email protected]

EPSS history

Timeline

18 AUG 12:23Z
Information disclosure due to side-channel in the Storage: Cache API component
cvelistv5