CVE-2026-0881 — Improper Access Control in Mozilla Firefox

CWE-284 — Improper Access ControlCWE-693 — Protection Mechanism Failure9 documents8 sources
Severity
10.0CRITICALNVD
EPSS
0.0%
top 91.88%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Mozilla FirefoxMozilla Thunderbird
Timeline
PublishedJan 13

Description

Sandbox escape in the Messaging System component. This vulnerability was fixed in Firefox 147 and Thunderbird 147.

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 Packages2 packages

▶NVDmozilla/firefox< 147.0
▶NVDmozilla/thunderbird< 147.0

🔴Vulnerability Details

3
OSV
CVE-2026-0881: Sandbox escape in the Messaging System component↗2026-01-13
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GHSA
GHSA-cw2j-6pvw-7g9v: Sandbox escape in the Messaging System component↗2026-01-13
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CVEList
Sandbox escape in the Messaging System component↗2026-01-13
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📋Vendor Advisories

4
Red Hat
firefox: Sandbox escape in the Messaging System component↗2026-01-13
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Debian
CVE-2026-0881: firefox - Sandbox escape in the Messaging System component. This vulnerability affects Fir...↗2026
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Mozilla
Mozilla Foundation Security Advisory 2026-01: CVE-2026-0881↗
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Mozilla
Mozilla Foundation Security Advisory 2026-04: CVE-2026-0881↗
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🕵️Threat Intelligence

1
Wiz
CVE-2026-0881 Impact, Exploitability, and Mitigation Steps | Wiz↗
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CVE-2026-0881 — Improper Access Control in Mozilla | cvebase