CVE-2025-9187

Name: CVE-2025-9187
Creator: NVD / NIST
Published: 2025-08-19T21:15:31.303+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 0.42%

Last modified Jun 17, 2026

CVE-2025-9187 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. Memory safety bugs present in Firefox 141 and Thunderbird 141. 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. EPSS estimates a 0.42% chance of exploitation in the next 30 days.

Description

Memory safety bugs present in Firefox 141 and Thunderbird 141. 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 was fixed in Firefox 142 and Thunderbird 142.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

0.42%

33.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-119

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 142.0
Mozilla	Thunderbird	< 142.0

References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1825621%2C1970079%2C1976736%2C1979072Broken Link
https://www.mozilla.org/security/advisories/mfsa2025-64/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-70/Vendor Advisory

Timeline

Published: Aug 19, 2025
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2025-9187?

How severe is CVE-2025-9187?

CVE-2025-9187 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.42% probability of exploitation in the next 30 days.

How do I fix CVE-2025-9187?

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-2025-9187?

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

Scan your code now

Source: NVD / NIST