CVE-2026-8391

high

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.

References

https://www.mozilla.org/security/advisories/mfsa2026-51/

https://www.mozilla.org/security/advisories/mfsa2026-48/

https://www.mozilla.org/security/advisories/mfsa2026-47/

https://www.mozilla.org/security/advisories/mfsa2026-45/

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8391.json

https://bugzilla.redhat.com/show_bug.cgi?id=2476475

https://bugzilla.mozilla.org/show_bug.cgi?id=2038575

https://access.redhat.com/security/cve/CVE-2026-8391

https://access.redhat.com/errata/RHSA-2026:27715

https://access.redhat.com/errata/RHSA-2026:26630

https://access.redhat.com/errata/RHSA-2026:26629

https://access.redhat.com/errata/RHSA-2026:26606

https://access.redhat.com/errata/RHSA-2026:26551

https://access.redhat.com/errata/RHSA-2026:26539

https://access.redhat.com/errata/RHSA-2026:26536

https://access.redhat.com/errata/RHSA-2026:26521

https://access.redhat.com/errata/RHSA-2026:26493

https://access.redhat.com/errata/RHSA-2026:26492

https://access.redhat.com/errata/RHSA-2026:26491

https://access.redhat.com/errata/RHSA-2026:26270

https://access.redhat.com/errata/RHSA-2026:26269

https://access.redhat.com/errata/RHSA-2026:26268

https://access.redhat.com/errata/RHSA-2026:26174

https://access.redhat.com/errata/RHSA-2026:22643

https://access.redhat.com/errata/RHSA-2026:22325

https://access.redhat.com/errata/RHSA-2026:21382

https://access.redhat.com/errata/RHSA-2026:21381

https://access.redhat.com/errata/RHSA-2026:21380

https://access.redhat.com/errata/RHSA-2026:21378

Details

Source: Mitre, NVD

Published: 2026-05-12

Updated: 2026-06-30

Risk Information

CVSS v2

Base Score: 7.6

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:C

Severity: High

CVSS v3

Base Score: 7.5

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H