Description
A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level document's process instead of the intended frame, potentially enabling a sandbox escape. This vulnerability was fixed in Firefox 138, Firefox ESR 128.10, Firefox ESR 115.23, Thunderbird 138, and Thunderbird 128.10.
Affected products
mozilla: firefox; mozilla: thunderbird
References7
- www.mozilla.org/security/advisories/mfsa2025-28/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2025-29/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2025-30/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2025-31/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2025-32/ Vendor Advisory
- bugzilla.mozilla.org/show_bug.cgi?id=1958350 Permissions Required
- lists.debian.org/debian-lts-announce/2025/05/msg00024.html
Metrics
- CVSS 3.1
-
9.1
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - EPSS — exploit probability
- 0% percentile: 40 · as of 7 November 2026
- CWE
- CWE-653
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