CVE-2026-100809CWE-346

CVE-2026-100809

High · published September 29, 2026

CVSS v3.1
8.1
EPSS
0%
Percentile
4.1
In the wild
Unconfirmed
What it is

Same-origin policy bypass in the DevTools component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.

The record
Technical detail
CVSS v3.1
8.1 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00153 · 4.1th percentile
Weakness
CWE-346 · Origin Validation Error
Published
2026-09-29T17:17Z
Affected products (4)
ProductVersionsFixed in
mozilla/firefox< 153.4.0153.4.0
mozilla/firefox≥ 154.0.0, < 157.0.0157.0.0
mozilla/thunderbird< 153.4.0153.4.0
mozilla/thunderbird≥ 154.0, < 157.0157.0
References (5)
https://bugzilla.mozilla.org/show_bug.cgi?id=2063658 · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-100/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-101/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-103/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-97/ · [email protected]
EPSS history
Timeline
  • 01 OCT 03:44Z
    EPSS moved — → 0%
    epss
  • 29 SEP 12:36Z
    Same-origin policy bypass in the DevTools component
    cvelistv5