CVE-2026-4689
published 2026-03-24CVE-2026-4689: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34…
PriorityP352critical10CVSS 3.1
AVNACLPRNUINSCCHIHAH
EPSS
0.66%
48.0th percentile
Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
Affected
13 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | firefox | < firefox 149.0-1 (sid) | firefox 149.0-1 (sid) |
| debian | firefox-esr | < firefox 149.0-1 (sid) | firefox 149.0-1 (sid) |
| debian | thunderbird | < firefox 149.0-1 (sid) | firefox 149.0-1 (sid) |
| mozilla | firefox | < 115.34.0 | 115.34.0 |
| mozilla | firefox | < 149.0 | 149.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 128.0 < 140.9.0 | 140.9.0 |
| mozilla | thunderbird | < 140.9.0 | 140.9.0 |
| mozilla | thunderbird | < 149.0 | 149.0 |
| mozilla | thunderbird | >= 0 < 1:140.9.0esr-1~deb11u1 | 1:140.9.0esr-1~deb11u1 |
| mozilla | thunderbird | >= 0 < 1:140.9.0esr-1~deb12u1 | 1:140.9.0esr-1~deb12u1 |
| mozilla | thunderbird | >= 0 < 1:140.9.0esr-1~deb13u1 | 1:140.9.0esr-1~deb13u1 |
| mozilla | thunderbird | >= 0 < 1:140.9.0esr-1 | 1:140.9.0esr-1 |
CVSS provenance
nvdv3.110.0CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
osv10.0CRITICAL
vendor_debian10.0CRITICAL
vendor_redhat10.0CRITICAL
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Red Hat
firefox: thunderbird: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component
vendor_redhat·2026-03-24·CVSS 10.0
CVE-2026-4689 [CRITICAL] CWE-190 firefox: thunderbird: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component
firefox: thunderbird: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component
Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/thunderbird-flatpak (Red Hat
Debian
CVE-2026-4689: firefox - Sandbox escape due to incorrect boundary conditions, integer overflow in the XPC...
vendor_debian·2026·CVSS 10.0
CVE-2026-4689 [CRITICAL] CVE-2026-4689: firefox - Sandbox escape due to incorrect boundary conditions, integer overflow in the XPC...
Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
Scope: local
sid: resolved (fixed in 149.0-1)
Mozilla
Mozilla Foundation Security Advisory 2026-24: CVE-2026-4689
vendor_mozilla·CVSS 10.0
CVE-2026-4689 [CRITICAL] Mozilla Foundation Security Advisory 2026-24: CVE-2026-4689
Mozilla Foundation Security Advisory 2026-24
CVE: CVE-2026-4689
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.9
Mozilla
Mozilla Foundation Security Advisory 2026-21: CVE-2026-4689
vendor_mozilla·CVSS 10.0
CVE-2026-4689 [CRITICAL] Mozilla Foundation Security Advisory 2026-21: CVE-2026-4689
Mozilla Foundation Security Advisory 2026-21
CVE: CVE-2026-4689
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 115.34
Mozilla
Mozilla Foundation Security Advisory 2026-20: CVE-2026-4689
vendor_mozilla·CVSS 10.0
CVE-2026-4689 [CRITICAL] Mozilla Foundation Security Advisory 2026-20: CVE-2026-4689
Mozilla Foundation Security Advisory 2026-20
CVE: CVE-2026-4689
Product: Firefox
Impact: high
Fixed in: Firefox 149
Mozilla
Mozilla Foundation Security Advisory 2026-23: CVE-2026-4689
vendor_mozilla·CVSS 10.0
CVE-2026-4689 [CRITICAL] Mozilla Foundation Security Advisory 2026-23: CVE-2026-4689
Mozilla Foundation Security Advisory 2026-23
CVE: CVE-2026-4689
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 149
Mozilla
Mozilla Foundation Security Advisory 2026-22: CVE-2026-4689
vendor_mozilla·CVSS 10.0
CVE-2026-4689 [CRITICAL] Mozilla Foundation Security Advisory 2026-22: CVE-2026-4689
Mozilla Foundation Security Advisory 2026-22
CVE: CVE-2026-4689
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.9
OSV
CVE-2026-4689: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component
osv·2026-03-24·CVSS 10.0
CVE-2026-4689 [CRITICAL] CVE-2026-4689: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component
Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
GHSA
GHSA-j5qx-hh9g-j6wj: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component
ghsa_unreviewed·2026-03-24
CVE-2026-4689 [CRITICAL] CWE-120 GHSA-j5qx-hh9g-j6wj: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component
Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, and Firefox ESR < 140.9.
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-4689 firefox: thunderbird: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component
bugzilla·2026-03-24·CVSS 10.0
CVE-2026-4689 [CRITICAL] CVE-2026-4689 firefox: thunderbird: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component
CVE-2026-4689 firefox: thunderbird: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component
Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, and Firefox ESR < 140.9.
Discussion:
This issue has been addressed in the following products:
Red Hat Enterprise Linux 10
Via RHSA-2026:5931 https://access.redhat.com/errata/RHSA-2026:5931
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2026:5930 https://access.redhat.com/errata/RHSA-2026:5930
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8
Via RHSA-2026:5932 https://access.redhat.com/errata/RHSA-2026:5932
Wiz
CVE-2026-4689 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 10.0
CVE-2026-4689 [CRITICAL] CVE-2026-4689 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-4689 :
NixOS vulnerability analysis and mitigation
Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
Source : NVD
## 10
Score
Published March 24, 2026
Severity CRITICAL
CNA Score 10.0
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) 7.6
Exploitation Probability (EPSS) N/A
Affected packages and libraries
MozillaFirefox
MozillaFirefox-translations-other
Sources
AlmaLinux 8 Severity HIGH Has Fix Added at: Mar 31, 2026
AlmaLinux 9 Severity HIGH Has Fix Added
https://bugzilla.mozilla.org/show_bug.cgi?id=2016374https://www.mozilla.org/security/advisories/mfsa2026-20/https://www.mozilla.org/security/advisories/mfsa2026-21/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/errata/RHSA-2026:5930https://access.redhat.com/errata/RHSA-2026:5931https://access.redhat.com/errata/RHSA-2026:5932https://access.redhat.com/errata/RHSA-2026:6188https://access.redhat.com/errata/RHSA-2026:6342https://access.redhat.com/errata/RHSA-2026:6917https://access.redhat.com/errata/RHSA-2026:7837https://access.redhat.com/errata/RHSA-2026:7838https://access.redhat.com/errata/RHSA-2026:7839https://access.redhat.com/errata/RHSA-2026:7840https://access.redhat.com/errata/RHSA-2026:7841https://access.redhat.com/errata/RHSA-2026:7842https://access.redhat.com/errata/RHSA-2026:7843https://access.redhat.com/errata/RHSA-2026:7845https://access.redhat.com/errata/RHSA-2026:7858https://access.redhat.com/errata/RHSA-2026:8284https://access.redhat.com/errata/RHSA-2026:8285https://access.redhat.com/errata/RHSA-2026:8286https://access.redhat.com/errata/RHSA-2026:8287https://access.redhat.com/errata/RHSA-2026:8288https://access.redhat.com/errata/RHSA-2026:8289https://access.redhat.com/errata/RHSA-2026:8290https://access.redhat.com/errata/RHSA-2026:8315https://access.redhat.com/errata/RHSA-2026:8427https://access.redhat.com/errata/RHSA-2026:8850https://access.redhat.com/security/cve/CVE-2026-4689https://bugzilla.redhat.com/show_bug.cgi?id=2450718https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4689.json
2026-03-24
Published