CVE-2026-5735

CWE-787 — Out-of-bounds Write9 documents8 sources
Severity
9.8CRITICAL
EPSS
0.1%
top 83.67%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Mozilla FirefoxMozilla Thunderbird
Timeline
PublishedApr 7

Description

Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. 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 < 149.0.2 and Thunderbird < 149.0.2.

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 Packages4 packages

▶CVEListV5mozilla/firefoxunspecified — 149.0.2
▶NVDmozilla/firefox< 149.0.2
▶CVEListV5mozilla/thunderbirdunspecified — 149.0.2
▶NVDmozilla/thunderbird< 149.0.2

🔴Vulnerability Details

2
GHSA
GHSA-rrjf-ccr2-ph7g: Memory safety bugs present in Firefox 149↗2026-04-07
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CVEList
Memory safety bugs fixed in Firefox 149.0.2 and Thunderbird 149.0.2↗2026-04-07
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📋Vendor Advisories

4
Red Hat
thunderbird: firefox: Memory safety bugs fixed in Firefox 149.0.2 and Thunderbird 149.0.2↗2026-04-07
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Debian
CVE-2026-5735: firefox - Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. Some of t...↗2026
▶
Mozilla
Mozilla Foundation Security Advisory 2026-25: CVE-2026-5735↗
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Mozilla
Mozilla Foundation Security Advisory 2026-28: CVE-2026-5735↗
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🕵️Threat Intelligence

1
Wiz
CVE-2026-5735 Impact, Exploitability, and Mitigation Steps | Wiz↗
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💬Community

1
Bugzilla
CVE-2026-5735 thunderbird: firefox: Memory safety bugs fixed in Firefox 149.0.2 and Thunderbird 149.0.2↗2026-04-07
▶
CVE-2026-5735 (CRITICAL CVSS 9.8) | Memory safety bugs present in Firef | cvebase.io