CVE-2026-8391

Other issue in the JavaScript Engine component

Published May 12, 2026 CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4592-1 firefox-esr security update
Debian DLA Debian DLA DLA-4594-1 thunderbird security update
Debian DSA Debian DSA DSA-6283-1 firefox-esr security update
Debian DSA Debian DSA DSA-6288-1 thunderbird security update
References
Link Providers
https://access.redhat.com/errata/RHSA-2026:21378 cve-icon
https://access.redhat.com/errata/RHSA-2026:21380 cve-icon
https://access.redhat.com/errata/RHSA-2026:21381 cve-icon
https://access.redhat.com/errata/RHSA-2026:21382 cve-icon
https://access.redhat.com/errata/RHSA-2026:22325 cve-icon
https://access.redhat.com/errata/RHSA-2026:22643 cve-icon
https://access.redhat.com/errata/RHSA-2026:26174 cve-icon
https://access.redhat.com/errata/RHSA-2026:26268 cve-icon
https://access.redhat.com/errata/RHSA-2026:26269 cve-icon
https://access.redhat.com/errata/RHSA-2026:26270 cve-icon
https://access.redhat.com/errata/RHSA-2026:26491 cve-icon
https://access.redhat.com/errata/RHSA-2026:26492 cve-icon
https://access.redhat.com/errata/RHSA-2026:26493 cve-icon
https://access.redhat.com/errata/RHSA-2026:26521 cve-icon
https://access.redhat.com/errata/RHSA-2026:26536 cve-icon
https://access.redhat.com/errata/RHSA-2026:26539 cve-icon
https://access.redhat.com/errata/RHSA-2026:26551 cve-icon
https://access.redhat.com/errata/RHSA-2026:26606 cve-icon
https://access.redhat.com/errata/RHSA-2026:26629 cve-icon
https://access.redhat.com/errata/RHSA-2026:26630 cve-icon
https://access.redhat.com/errata/RHSA-2026:27715 cve-icon
https://access.redhat.com/security/cve/CVE-2026-8391 cve-icon
https://bugzilla.mozilla.org/show_bug.cgi?id=2038575 cve-icon cve-icon
https://bugzilla.redhat.com/show_bug.cgi?id=2476475 cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-8391 cve-icon
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8391.json cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-8391 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-45/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-45/#CVE-2026-8391 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-47/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-48/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-48/#CVE-2026-8391 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-51/ cve-icon cve-icon
History
Type Values Removed Values Added
Description Other issue in the JavaScript Engine component. This vulnerability was fixed in Firefox 150.0.3, Firefox ESR 115.36, and Firefox ESR 140.11. 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
Type Values Removed Values Added
Description Other issue in the JavaScript Engine component. This vulnerability was fixed in Firefox 150.0.3. Other issue in the JavaScript Engine component. This vulnerability was fixed in Firefox 150.0.3, Firefox ESR 115.36, and Firefox ESR 140.11.
References
Type Values Removed Values Added
Weaknesses CWE-94
Type Values Removed Values Added
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
Type Values Removed Values Added
Weaknesses CWE-119
CWE-20
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Weaknesses CWE-79
CWE-94
Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox
Type Values Removed Values Added
Description Other issue in the JavaScript Engine component. This vulnerability was fixed in Firefox 150.0.3.
Title Other issue in the JavaScript Engine component
References

Sources

Status
PUBLISHED
Assigner
mozilla
Published
Updated
Jul 15, 2026, 2:47 AM
Reserved
May 12, 2026, 12:36 PM
Status
Modified
Published
May 12, 2026, 2:17 PM
Modified
Oct 25, 2026, 11:10 PM
Severity
Important
Public date
May 12, 2026, 12:36 PM