CVE-2026-2793
published 2026-02-24CVE-2026-2793: Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147. Some of these bugs showed evidence…
PriorityP350critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EPSS
0.31%
23.5th percentile
Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147. 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 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
Affected
13 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | firefox | < firefox 148.0-1 (sid) | firefox 148.0-1 (sid) |
| debian | firefox-esr | < firefox 148.0-1 (sid) | firefox 148.0-1 (sid) |
| debian | thunderbird | < firefox 148.0-1 (sid) | firefox 148.0-1 (sid) |
| mozilla | firefox | < 115.33.0 | 115.33.0 |
| mozilla | firefox | < 148.0 | 148.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 128.0 < 140.8.0 | 140.8.0 |
| mozilla | thunderbird | < 140.8.0 | 140.8.0 |
| mozilla | thunderbird | < 148.0 | 148.0 |
| mozilla | thunderbird | >= 0 < 1:140.8.0esr-1~deb11u1 | 1:140.8.0esr-1~deb11u1 |
| mozilla | thunderbird | >= 0 < 1:140.8.0esr-1~deb12u1 | 1:140.8.0esr-1~deb12u1 |
| mozilla | thunderbird | >= 0 < 1:140.8.0esr-1~deb13u1 | 1:140.8.0esr-1~deb13u1 |
| mozilla | thunderbird | >= 0 < 1:140.8.0esr-1 | 1:140.8.0esr-1 |
CVSS provenance
nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
osv9.8CRITICAL
vendor_debian9.8CRITICAL
vendor_redhat9.8CRITICAL
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Red Hat
firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148
vendor_redhat·2026-02-24·CVSS 9.8
CVE-2026-2793 [CRITICAL] firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148
firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148
Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147. 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 < 148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147
Debian
CVE-2026-2793: firefox - Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird...
vendor_debian·2026·CVSS 9.8
CVE-2026-2793 [CRITICAL] CVE-2026-2793: firefox - Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird...
Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147. 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 < 148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
Scope: local
sid: resolved (fixed in 148.0-1)
Mozilla
Mozilla Foundation Security Advisory 2026-13: CVE-2026-2793
vendor_mozilla·CVSS 9.8
CVE-2026-2793 [CRITICAL] Mozilla Foundation Security Advisory 2026-13: CVE-2026-2793
Mozilla Foundation Security Advisory 2026-13
CVE: CVE-2026-2793
Product: Firefox
Impact: high
Fixed in: Firefox 148
Mozilla
Mozilla Foundation Security Advisory 2026-17: CVE-2026-2793
vendor_mozilla·CVSS 9.8
CVE-2026-2793 [CRITICAL] Mozilla Foundation Security Advisory 2026-17: CVE-2026-2793
Mozilla Foundation Security Advisory 2026-17
CVE: CVE-2026-2793
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.8
Mozilla
Mozilla Foundation Security Advisory 2026-15: CVE-2026-2793
vendor_mozilla·CVSS 9.8
CVE-2026-2793 [CRITICAL] Mozilla Foundation Security Advisory 2026-15: CVE-2026-2793
Mozilla Foundation Security Advisory 2026-15
CVE: CVE-2026-2793
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.8
Mozilla
Mozilla Foundation Security Advisory 2026-14: CVE-2026-2793
vendor_mozilla·CVSS 9.8
CVE-2026-2793 [CRITICAL] Mozilla Foundation Security Advisory 2026-14: CVE-2026-2793
Mozilla Foundation Security Advisory 2026-14
CVE: CVE-2026-2793
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 115.33
Mozilla
Mozilla Foundation Security Advisory 2026-16: CVE-2026-2793
vendor_mozilla·CVSS 9.8
CVE-2026-2793 [CRITICAL] Mozilla Foundation Security Advisory 2026-16: CVE-2026-2793
Mozilla Foundation Security Advisory 2026-16
CVE: CVE-2026-2793
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 148
GHSA
GHSA-48q6-99pr-mcvm: Memory safety bugs present in Firefox ESR 115
ghsa_unreviewed·2026-02-24
CVE-2026-2793 [CRITICAL] CWE-787 GHSA-48q6-99pr-mcvm: Memory safety bugs present in Firefox ESR 115
Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147. 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 < 148, Firefox ESR < 115.33, and Firefox ESR < 140.8.
OSV
CVE-2026-2793: Memory safety bugs present in Firefox ESR 115
osv·2026-02-24·CVSS 9.8
CVE-2026-2793 [CRITICAL] CVE-2026-2793: Memory safety bugs present in Firefox ESR 115
Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147. 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 < 148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
No detection rules found.
No public exploits indexed.
Wiz
CVE-2026-2793 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 9.8
CVE-2026-2793 [CRITICAL] CVE-2026-2793 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-2793 :
NixOS vulnerability analysis and mitigation
Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147. 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 < 148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
Source : NVD
## 9.8
Score
Published February 24, 2026
Severity CRITICAL
CNA Score 9.8
Affected Technologies
NixOS
Mozilla Firefox
Has Public Exploit No
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 21.6
Exploitation Probability (EPSS) 0.
Bugzilla
CVE-2026-2793 firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148
bugzilla·2026-02-24·CVSS 9.8
CVE-2026-2793 [CRITICAL] CVE-2026-2793 firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148
CVE-2026-2793 firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148
Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147. 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 < 148, Firefox ESR < 115.33, and Firefox ESR < 140.8.
Discussion:
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8
Via RHSA-2026:3338 https://access.redhat.com/errata/RHSA-2026:3338
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2
https://bugzilla.mozilla.org/buglist.cgi?bug_id=2015196%2C2016423%2C2016498https://www.mozilla.org/security/advisories/mfsa2026-13/https://www.mozilla.org/security/advisories/mfsa2026-14/https://www.mozilla.org/security/advisories/mfsa2026-15/https://www.mozilla.org/security/advisories/mfsa2026-16/https://www.mozilla.org/security/advisories/mfsa2026-17/https://access.redhat.com/errata/RHSA-2026:3338https://access.redhat.com/errata/RHSA-2026:3339https://access.redhat.com/errata/RHSA-2026:3361https://access.redhat.com/errata/RHSA-2026:3491https://access.redhat.com/errata/RHSA-2026:3492https://access.redhat.com/errata/RHSA-2026:3493https://access.redhat.com/errata/RHSA-2026:3494https://access.redhat.com/errata/RHSA-2026:3495https://access.redhat.com/errata/RHSA-2026:3496https://access.redhat.com/errata/RHSA-2026:3497https://access.redhat.com/errata/RHSA-2026:3515https://access.redhat.com/errata/RHSA-2026:3516https://access.redhat.com/errata/RHSA-2026:3517https://access.redhat.com/errata/RHSA-2026:3976https://access.redhat.com/errata/RHSA-2026:3978https://access.redhat.com/errata/RHSA-2026:3979https://access.redhat.com/errata/RHSA-2026:3980https://access.redhat.com/errata/RHSA-2026:3981https://access.redhat.com/errata/RHSA-2026:3982https://access.redhat.com/errata/RHSA-2026:3983https://access.redhat.com/errata/RHSA-2026:3984https://access.redhat.com/errata/RHSA-2026:4022https://access.redhat.com/errata/RHSA-2026:4152https://access.redhat.com/errata/RHSA-2026:4260https://access.redhat.com/errata/RHSA-2026:4432https://access.redhat.com/security/cve/CVE-2026-2793https://bugzilla.redhat.com/show_bug.cgi?id=2442287https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-2793.json
2026-02-24
Published