by Kastro
Paper/Archive/CVE-2026-4729

CVE-2026-4729

Mozilla Firefox — Memory safety bugs fixed in Firefox 149 and Thunderbird 149

EPSS 0.3%CVSS 9.8
critical.is priorityof 100
35
CVSS 9.8 (ADP)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 27.9.279 × 205.6No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

Memory safety bugs present in Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 149 and Thunderbird 149.

Affected

ProductAffectedFixed inSource
Firefoxsee advisory149CNA
Thunderbirdsee advisory149CNA
Red Hat Enterprise Linux 10see advisory–redhat-SADP
Red Hat Enterprise Linux 10see advisory–redhat-SADP
Red Hat Enterprise Linux 6see advisory–redhat-SADP
Red Hat Enterprise Linux 7see advisory–redhat-SADP
Red Hat Enterprise Linux 8see advisory–redhat-SADP
Red Hat Enterprise Linux 9see advisory–redhat-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
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/buglist.cgi?bug_id=1944033%2C1997282%2C2009213%2C2011412%2C2021925%2C2022034refmozilla.org/security/advisories/mfsa2026-20refmozilla.org/security/advisories/mfsa2026-23refaccess.redhat.com/security/cve/CVE-2026-4729refbugzilla.redhat.com/show_bug.cgi?id=2450745refsecurity.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4729.json