CVE-2026-4701

CWE-416 — Use After FreeCWE-82512 documents9 sources
Severity
9.8CRITICAL
EPSS
0.0%
top 93.89%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
3
Mozilla FirefoxMozilla Firefox ESRMozilla Thunderbird
Timeline
PublishedMar 24

Description

Use-after-free in the JavaScript Engine component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitability: 3.9 | Impact: 5.9

Affected Packages6 packages

▶CVEListV5mozilla/firefoxunspecified — 149
▶NVDmozilla/firefox< 140.9.0+1
▶CVEListV5mozilla/firefox_esrunspecified — 140.9
▶CVEListV5mozilla/thunderbirdunspecified — 149+1
▶Debianfirefox-esr< 140.9.0esr-1~deb11u1+3

🔴Vulnerability Details

3
OSV
CVE-2026-4701: Use-after-free in the JavaScript Engine component↗2026-03-24
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CVEList
Use-after-free in the JavaScript Engine component↗2026-03-24
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GHSA
GHSA-hxpv-3x38-h8v5: Use-after-free in the JavaScript Engine component↗2026-03-24
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📋Vendor Advisories

6
Red Hat
firefox: thunderbird: Use-after-free in the JavaScript Engine component↗2026-03-24
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Debian
CVE-2026-4701: firefox - Use-after-free in the JavaScript Engine component. This vulnerability affects Fi...↗2026
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Mozilla
Mozilla Foundation Security Advisory 2026-23: CVE-2026-4701↗
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Mozilla
Mozilla Foundation Security Advisory 2026-22: CVE-2026-4701↗
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Mozilla
Mozilla Foundation Security Advisory 2026-20: CVE-2026-4701↗
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🕵️Threat Intelligence

1
Wiz
CVE-2026-4701 Impact, Exploitability, and Mitigation Steps | Wiz↗
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💬Community

1
Bugzilla
CVE-2026-4701 firefox: thunderbird: Use-after-free in the JavaScript Engine component↗2026-03-24
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