CVE-2026-100821CWE-346

CVE-2026-100821

Medium · published September 29, 2026

CVSS v3.1
4.7
EPSS
0%
Percentile
3.3
In the wild
Unconfirmed
What it is

Site isolation issue in the Panning and Zooming component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

The record
Technical detail
CVSS v3.1
4.7 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00143 · 3.3th percentile
Weakness
CWE-346 · Origin Validation Error
Published
2026-09-29T17:17Z
Affected products (7)
ProductVersionsFixed in
mozilla/firefox< 115.42.0115.42.0
mozilla/firefox≥ 116.0.0, < 140.17.0140.17.0
mozilla/firefox≥ 141.0.0, < 153.4.0153.4.0
mozilla/firefox≥ 154.0.0, < 157.0.0157.0.0
mozilla/thunderbird< 140.17.0140.17.0
mozilla/thunderbird≥ 141.0, < 153.4.0153.4.0
mozilla/thunderbird≥ 154.0, < 157.0157.0
References (8)
https://bugzilla.mozilla.org/show_bug.cgi?id=2071784 · [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/mfsa2026-102/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-103/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-97/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-98/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-99/ · [email protected]
EPSS history
Timeline
  • 01 OCT 03:44Z
    EPSS moved — → 0%
    epss
  • 29 SEP 12:36Z
    Site isolation issue in the Panning and Zooming component
    cvelistv5