CVE-2026-4689

CWE-190 — Integer OverflowCWE-754CWE-120 — Classic Buffer Overflow13 documents9 sources
Severity
10.0CRITICAL
EPSS
0.0%
top 92.38%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
3
Mozilla FirefoxMozilla Firefox ESRMozilla Thunderbird
Timeline
PublishedMar 24

Description

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.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HExploitability: 3.9 | Impact: 6.0

Affected Packages7 packages

▶CVEListV5mozilla/firefoxunspecified — 149
▶NVDmozilla/firefox128.0 — 140.9.0+2
▶CVEListV5mozilla/firefox_esrunspecified — 115.34+1
▶Debianfirefox-esr< 140.9.0esr-1~deb11u1+3
▶CVEListV5mozilla/thunderbirdunspecified — 149+1

🔴Vulnerability Details

3
CVEList
Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component↗2026-03-24
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OSV
CVE-2026-4689: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component↗2026-03-24
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GHSA
GHSA-j5qx-hh9g-j6wj: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component↗2026-03-24
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📋Vendor Advisories

7
Red Hat
firefox: thunderbird: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component↗2026-03-24
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Debian
CVE-2026-4689: firefox - Sandbox escape due to incorrect boundary conditions, integer overflow in the XPC...↗2026
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Mozilla
Mozilla Foundation Security Advisory 2026-24: CVE-2026-4689↗
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Mozilla
Mozilla Foundation Security Advisory 2026-21: CVE-2026-4689↗
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Mozilla
Mozilla Foundation Security Advisory 2026-20: CVE-2026-4689↗
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🕵️Threat Intelligence

1
Wiz
CVE-2026-4689 Impact, Exploitability, and Mitigation Steps | Wiz↗
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💬Community

1
Bugzilla
CVE-2026-4689 firefox: thunderbird: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component↗2026-03-24
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CVE-2026-4689 (CRITICAL CVSS 10) | Sandbox escape due to incorrect bou | cvebase.io