Memory safety bugs fixed in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149 (Mozilla Firefox)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.44 % · percentile 38 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- mozilla
- NVD status
- Modified
Description
Memory safety bugs present in Firefox ESR 140.8, Thunderbird ESR 140.8, 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, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
Weaknesses (CWE)
- CWE-120 — Buffer Copy without Checking Size of Input
References
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=2004652%2C2019372%2C2021922%2C2022567%2C2022733
- https://www.mozilla.org/security/advisories/mfsa2026-20/
- https://www.mozilla.org/security/advisories/mfsa2026-22/
- https://www.mozilla.org/security/advisories/mfsa2026-23/
- https://www.mozilla.org/security/advisories/mfsa2026-24/
- https://access.redhat.com/security/cve/CVE-2026-4720
- https://bugzilla.redhat.com/show_bug.cgi?id=2450751
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4720.json
- https://access.redhat.com/errata/RHSA-2026:8427
- https://access.redhat.com/errata/RHSA-2026:7843
- https://access.redhat.com/errata/RHSA-2026:8315
- https://access.redhat.com/errata/RHSA-2026:5931
- https://access.redhat.com/errata/RHSA-2026:6342
- https://access.redhat.com/errata/RHSA-2026:5932
- https://access.redhat.com/errata/RHSA-2026:6917
- https://access.redhat.com/errata/RHSA-2026:7840
- https://access.redhat.com/errata/RHSA-2026:8285
- https://access.redhat.com/errata/RHSA-2026:7858
- https://access.redhat.com/errata/RHSA-2026:8850
- https://access.redhat.com/errata/RHSA-2026:7842
- https://access.redhat.com/errata/RHSA-2026:8289
- https://access.redhat.com/errata/RHSA-2026:7838
- https://access.redhat.com/errata/RHSA-2026:8288
- https://access.redhat.com/errata/RHSA-2026:7839
- https://access.redhat.com/errata/RHSA-2026:8286
- https://access.redhat.com/errata/RHSA-2026:7841
- https://access.redhat.com/errata/RHSA-2026:8287
- https://access.redhat.com/errata/RHSA-2026:7845
- https://access.redhat.com/errata/RHSA-2026:8290
- https://access.redhat.com/errata/RHSA-2026:7837
- https://access.redhat.com/errata/RHSA-2026:8284
- https://access.redhat.com/errata/RHSA-2026:5930
- https://access.redhat.com/errata/RHSA-2026:6188
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | CRITICAL 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | CISA-ADP |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H | redhat-SADP |
| CVSS 3.1 | CRITICAL 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
European references
- ENISA EUVD · EUVD-2026-14855
- GCVE · GCVE-0-2026-4720
CERT-FR advisories
- CERTFR-2026-AVI-0354 — Multiples vulnérabilités dans les produits Mozilla · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*< 140.9.0cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*< 149.0cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*< 140.9.0cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*< 149.0
Affected products
| Product | Versions |
|---|---|
| Mozilla · Firefox | unaffected 140.9 ≤ 140.* ; unaffected 149 ≤ * |
| Mozilla · Thunderbird | unaffected 140.9 ≤ 140.* ; unaffected 149 ≤ * |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |