CVE-2026-0881

Name: CVE-2026-0881
Creator: NVD / NIST
Published: 2026-01-13T14:16:38.657+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 10/10EPSS 0.37%

Last modified Jun 17, 2026

CVE-2026-0881 is a critical-severity vulnerability rated 10/10 on the CVSS scale. Sandbox escape in the Messaging System component. This vulnerability was fixed in Firefox 147 and Thunderbird 147.. EPSS estimates a 0.37% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1

10/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS Probability

0.37%

29.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 147.0
Mozilla	Thunderbird	< 147.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2005845Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-01/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-04/Vendor Advisory

Timeline

Published: Jan 13, 2026
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2026-0881?

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

How severe is CVE-2026-0881?

CVE-2026-0881 has a CVSS score of 10/10 (CRITICAL severity). The EPSS model estimates a 0.37% probability of exploitation in the next 30 days.

How do I fix CVE-2026-0881?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-0881?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST