VulnerabilityModified
CVE-2026-8401
This vulnerability was fixed in Firefox 150.0.3, Firefox ESR 115.36, Firefox ESR 140.11, and Thunderbird 140.11.
CRITICAL 9.8EPSS 0.31%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.31%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Sandbox escape in the Profile Backup component. This vulnerability was fixed in Firefox 150.0.3, Firefox ESR 115.36, Firefox ESR 140.11, and Thunderbird 140.11.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.31% probability · 24th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-693, CWE-653
- Affected
- mozilla/firefox
- Source
- security@mozilla.org
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2038679Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-45/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-47/
- https://www.mozilla.org/security/advisories/mfsa2026-48/
- https://www.mozilla.org/security/advisories/mfsa2026-51/
- https://access.redhat.com/errata/RHSA-2026:21378
- https://access.redhat.com/errata/RHSA-2026:21380
- https://access.redhat.com/errata/RHSA-2026:21381
- https://access.redhat.com/errata/RHSA-2026:21382
- https://access.redhat.com/errata/RHSA-2026:22325
- https://access.redhat.com/errata/RHSA-2026:22643
- https://access.redhat.com/errata/RHSA-2026:26174
- https://access.redhat.com/errata/RHSA-2026:26268
- https://access.redhat.com/errata/RHSA-2026:26269
- https://access.redhat.com/errata/RHSA-2026:26270
- https://access.redhat.com/errata/RHSA-2026:26491
- https://access.redhat.com/errata/RHSA-2026:26492
- https://access.redhat.com/errata/RHSA-2026:26493
- https://access.redhat.com/errata/RHSA-2026:26521
- https://access.redhat.com/errata/RHSA-2026:26536
- https://access.redhat.com/errata/RHSA-2026:26539
- https://access.redhat.com/errata/RHSA-2026:26551
- https://access.redhat.com/errata/RHSA-2026:26606
- https://access.redhat.com/errata/RHSA-2026:26629
- https://access.redhat.com/errata/RHSA-2026:26630
- https://access.redhat.com/errata/RHSA-2026:27715
- https://access.redhat.com/security/cve/CVE-2026-8401
- https://bugzilla.redhat.com/show_bug.cgi?id=2476492
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8401.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.