CVE-2026-4720

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.
References
Link Resource
https://bugzilla.mozilla.org/buglist.cgi?bug_id=2004652%2C2019372%2C2021922%2C2022567%2C2022733 Broken Link
https://www.mozilla.org/security/advisories/mfsa2026-20/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-22/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-23/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-24/ Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:5930
https://access.redhat.com/errata/RHSA-2026:5931
https://access.redhat.com/errata/RHSA-2026:5932
https://access.redhat.com/errata/RHSA-2026:6188
https://access.redhat.com/errata/RHSA-2026:6342
https://access.redhat.com/errata/RHSA-2026:6917
https://access.redhat.com/errata/RHSA-2026:7837
https://access.redhat.com/errata/RHSA-2026:7838
https://access.redhat.com/errata/RHSA-2026:7839
https://access.redhat.com/errata/RHSA-2026:7840
https://access.redhat.com/errata/RHSA-2026:7841
https://access.redhat.com/errata/RHSA-2026:7842
https://access.redhat.com/errata/RHSA-2026:7843
https://access.redhat.com/errata/RHSA-2026:7845
https://access.redhat.com/errata/RHSA-2026:7858
https://access.redhat.com/errata/RHSA-2026:8284
https://access.redhat.com/errata/RHSA-2026:8285
https://access.redhat.com/errata/RHSA-2026:8286
https://access.redhat.com/errata/RHSA-2026:8287
https://access.redhat.com/errata/RHSA-2026:8288
https://access.redhat.com/errata/RHSA-2026:8289
https://access.redhat.com/errata/RHSA-2026:8290
https://access.redhat.com/errata/RHSA-2026:8315
https://access.redhat.com/errata/RHSA-2026:8427
https://access.redhat.com/errata/RHSA-2026:8850
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
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*

History

30 Jun 2026, 03:20

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:5930 -
  • () https://access.redhat.com/errata/RHSA-2026:5931 -
  • () https://access.redhat.com/errata/RHSA-2026:5932 -
  • () https://access.redhat.com/errata/RHSA-2026:6188 -
  • () https://access.redhat.com/errata/RHSA-2026:6342 -
  • () https://access.redhat.com/errata/RHSA-2026:6917 -
  • () https://access.redhat.com/errata/RHSA-2026:7837 -
  • () https://access.redhat.com/errata/RHSA-2026:7838 -
  • () https://access.redhat.com/errata/RHSA-2026:7839 -
  • () https://access.redhat.com/errata/RHSA-2026:7840 -
  • () https://access.redhat.com/errata/RHSA-2026:7841 -
  • () https://access.redhat.com/errata/RHSA-2026:7842 -
  • () https://access.redhat.com/errata/RHSA-2026:7843 -
  • () https://access.redhat.com/errata/RHSA-2026:7845 -
  • () https://access.redhat.com/errata/RHSA-2026:7858 -
  • () https://access.redhat.com/errata/RHSA-2026:8284 -
  • () https://access.redhat.com/errata/RHSA-2026:8285 -
  • () https://access.redhat.com/errata/RHSA-2026:8286 -
  • () https://access.redhat.com/errata/RHSA-2026:8287 -
  • () https://access.redhat.com/errata/RHSA-2026:8288 -
  • () https://access.redhat.com/errata/RHSA-2026:8289 -
  • () https://access.redhat.com/errata/RHSA-2026:8290 -
  • () https://access.redhat.com/errata/RHSA-2026:8315 -
  • () https://access.redhat.com/errata/RHSA-2026:8427 -
  • () https://access.redhat.com/errata/RHSA-2026:8850 -
  • () 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 -

13 Apr 2026, 15:17

Type Values Removed Values Added
Summary (en) 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 affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9. (en) 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.

25 Mar 2026, 20:56

Type Values Removed Values Added
First Time Mozilla
Mozilla firefox
Mozilla thunderbird
CPE cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
References () https://bugzilla.mozilla.org/buglist.cgi?bug_id=2004652%2C2019372%2C2021922%2C2022567%2C2022733 - () https://bugzilla.mozilla.org/buglist.cgi?bug_id=2004652%2C2019372%2C2021922%2C2022567%2C2022733 - Broken Link
References () https://www.mozilla.org/security/advisories/mfsa2026-20/ - () https://www.mozilla.org/security/advisories/mfsa2026-20/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-22/ - () https://www.mozilla.org/security/advisories/mfsa2026-22/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-23/ - () https://www.mozilla.org/security/advisories/mfsa2026-23/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-24/ - () https://www.mozilla.org/security/advisories/mfsa2026-24/ - Vendor Advisory

25 Mar 2026, 14:16

Type Values Removed Values Added
Summary
  • (es) Errores de seguridad de memoria presentes en Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 y Thunderbird 148. Algunos de estos errores mostraron evidencia de corrupción de memoria y presumimos que con suficiente esfuerzo algunos de estos podrían haber sido explotados para ejecutar código arbitrario. Esta vulnerabilidad afecta a Firefox &lt; 149, Firefox ESR &lt; 140.9, Thunderbird &lt; 149 y Thunderbird &lt; 140.9.
CWE CWE-120
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 9.8

24 Mar 2026, 21:16

Type Values Removed Values Added
Summary (en) 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 affects Firefox < 149 and Firefox ESR < 140.9. (en) 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 affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
References
  • () https://www.mozilla.org/security/advisories/mfsa2026-23/ -
  • () https://www.mozilla.org/security/advisories/mfsa2026-24/ -

24 Mar 2026, 13:16

Type Values Removed Values Added
New CVE

Information

Published : 2026-03-24 13:16

Updated : 2026-07-15 02:22


NVD link : CVE-2026-4720

Mitre link : CVE-2026-4720

CVE.ORG link : CVE-2026-4720


JSON object : View

Products Affected

mozilla

  • firefox
  • thunderbird
CWE
CWE-120

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')