VulnerabilityModified
CVE-2026-8391
This vulnerability was fixed in Firefox 150.0.3, Firefox ESR 115.36, Firefox ESR 140.11, and Thunderbird 140.11.
MEDIUM 5.3EPSS 0.30%
Does this matter?
Lower severity and a low EPSS score (0.30%). Track it; it rarely justifies an emergency change on its own.
Description
Other issue in the JavaScript Engine 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
- 5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- EPSS
- 0.30% probability · 22th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-20, CWE-79, CWE-119, CWE-475
- Affected
- mozilla/firefox
- Source
- security@mozilla.org
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2038575Permissions 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-2026-8391
- https://bugzilla.redhat.com/show_bug.cgi?id=2476475
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8391.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.