CVE-2026-6786Memory safety bugs fixed in Firefox ESR 140.10, Thunderbird ESR 140.10, Firefox 150 and Thunderbird 150
Updated under an hour ago ()
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It affects Mozilla Firefox and 9 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Memory safety bugs present in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149. 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 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
- CVSS
- 7.5 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-416, CWE-125, CWE-787
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- mozilla
- NVD analysis
- Modified
- Record last updated
- Jul 14, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Mozilla Firefox mozilla:firefox (from the name) | 140.10 builds before 140.* not affected; from 150 not affected | CNA record |
Mozilla Thunderbird mozilla:thunderbird (from the name) | 140.10 builds before 140.* not affected; from 150 not affected | CNA record |
Red Hat Red Hat Enterprise Linux 10 redhat:enterprise_linux | from 0:140.10.0-1.el10_1 not affected; from 0:140.10.0-1.el10_2 not affected | CISA ADP |
Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support redhat:enterprise_linux_eus | from 0:140.10.0-1.el10_0 not affected | CISA ADP |
from 0:140.10.0-2.el7_9 not affected | CISA ADP | |
from 0:140.10.0-1.el8_4 not affected | CISA ADP | |
Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On redhat:rhel_eus_long_life | from 0:140.10.0-1.el8_4 not affected | CISA ADP |
from 0:140.10.0-1.el8_6 not affected | CISA ADP | |
from 0:140.10.0-1.el8_6 not affected | CISA ADP | |
Red Hat Red Hat Enterprise Linux 9.4 Extended Update Support redhat:rhel_eus | from 0:140.10.0-1.el9_4 not affected | CISA ADP |
mozilla firefox mozilla:firefox | before 150.0; from 140.0 before 140.10.0 | NVD |
mozilla thunderbird mozilla:thunderbird | from 140.0 before 140.10.0 | NVD |
References
- https://www.mozilla.org/security/advisories/mfsa2026-30/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-32/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-33/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-34/vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:10757
- https://access.redhat.com/errata/RHSA-2026:10766
- https://access.redhat.com/errata/RHSA-2026:10767
- https://access.redhat.com/errata/RHSA-2026:12285
- https://access.redhat.com/errata/RHSA-2026:13537
- https://access.redhat.com/errata/RHSA-2026:15892
- https://access.redhat.com/errata/RHSA-2026:17477
- https://access.redhat.com/errata/RHSA-2026:17687
- https://access.redhat.com/errata/RHSA-2026:17688
- https://access.redhat.com/errata/RHSA-2026:17689
- https://access.redhat.com/errata/RHSA-2026:17690
- https://access.redhat.com/errata/RHSA-2026:19041
- https://access.redhat.com/errata/RHSA-2026:19131
- https://access.redhat.com/errata/RHSA-2026:19201
- https://access.redhat.com/errata/RHSA-2026:19348
- https://access.redhat.com/errata/RHSA-2026:19461
- https://access.redhat.com/errata/RHSA-2026:19462
- https://access.redhat.com/errata/RHSA-2026:19463
- https://access.redhat.com/errata/RHSA-2026:19464
- https://access.redhat.com/errata/RHSA-2026:19465
- https://access.redhat.com/errata/RHSA-2026:19466
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.