Paper/Archive/CVE-2026-4691

CVE-2026-4691

Mozilla Firefox — Use-after-free in the CSS Parsing and Computation component

Description · from the CVE record

Use-after-free in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

Affected

ProductAffectedFixed inSource
Firefoxsee advisory115.34CNA
Thunderbirdsee advisory140.9CNA
Red Hat Enterprise Linux 10see advisory0:140.9.0-1.el10_1redhat-SADP
Red Hat Enterprise Linux 10see advisory0:140.9.0-1.el10_1redhat-SADP
Red Hat Enterprise Linux 10.0 Extended Update Supportsee advisory0:140.9.0-1.el10_0redhat-SADP
Red Hat Enterprise Linux 10.0 Extended Update Supportsee advisory0:140.9.0-1.el10_0redhat-SADP
Red Hat Enterprise Linux 7 Extended Lifecycle Supportsee advisory0:140.9.0-1.el7_9redhat-SADP
Red Hat Enterprise Linux 8see advisory0:140.9.0-1.el8_10redhat-SADP
Red Hat Enterprise Linux 8see advisory0:140.9.0-1.el8_10redhat-SADP
Red Hat Enterprise Linux 8.2 Advanced Update Supportsee advisory0:140.9.0-1.el8_2redhat-SADP
Red Hat Enterprise Linux 8.2 Advanced Update Supportsee advisory0:140.9.0-1.el8_2redhat-SADP
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Supportsee advisory0:140.9.0-1.el8_4redhat-SADP

Scores by source

CISA ADP9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
redhat-SADP (CNA)7.5CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refbugzilla.mozilla.org/show_bug.cgi?id=2017512refmozilla.org/security/advisories/mfsa2026-20refmozilla.org/security/advisories/mfsa2026-21refmozilla.org/security/advisories/mfsa2026-22refmozilla.org/security/advisories/mfsa2026-23refmozilla.org/security/advisories/mfsa2026-24refaccess.redhat.com/security/cve/CVE-2026-4691refbugzilla.redhat.com/show_bug.cgi?id=2450738refsecurity.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4691.jsonadvisoryaccess.redhat.com/errata/RHSA-2026:8427advisoryaccess.redhat.com/errata/RHSA-2026:7843advisoryaccess.redhat.com/errata/RHSA-2026:8315advisoryaccess.redhat.com/errata/RHSA-2026:5931advisoryaccess.redhat.com/errata/RHSA-2026:6342advisoryaccess.redhat.com/errata/RHSA-2026:5932advisoryaccess.redhat.com/errata/RHSA-2026:6917advisoryaccess.redhat.com/errata/RHSA-2026:7840advisoryaccess.redhat.com/errata/RHSA-2026:8285advisoryaccess.redhat.com/errata/RHSA-2026:7858advisoryaccess.redhat.com/errata/RHSA-2026:8850advisoryaccess.redhat.com/errata/RHSA-2026:7842advisoryaccess.redhat.com/errata/RHSA-2026:8289advisoryaccess.redhat.com/errata/RHSA-2026:7838advisoryaccess.redhat.com/errata/RHSA-2026:8288advisoryaccess.redhat.com/errata/RHSA-2026:7839advisoryaccess.redhat.com/errata/RHSA-2026:8286advisoryaccess.redhat.com/errata/RHSA-2026:7841advisoryaccess.redhat.com/errata/RHSA-2026:8287advisoryaccess.redhat.com/errata/RHSA-2026:7845advisoryaccess.redhat.com/errata/RHSA-2026:8290advisoryaccess.redhat.com/errata/RHSA-2026:7837advisoryaccess.redhat.com/errata/RHSA-2026:8284advisoryaccess.redhat.com/errata/RHSA-2026:5930advisoryaccess.redhat.com/errata/RHSA-2026:6188