CVE-2025-9187

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.

CVSS v3.1 Score

9.8

CRITICAL

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

Weakness Type (CWE)

CWE-119 Buffer Overflow

Affected Products

Vendor	Product	Versions
mozilla	firefox	< 142.0
mozilla	thunderbird	< 142.0

References

Advisories & Patches

https://www.mozilla.org/security/advisories/mfsa2025-64/ https://www.mozilla.org/security/advisories/mfsa2025-70/

Other References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1825621%2C1970079%2C1976736%2C1979072

Frequently Asked Questions

What is CVE-2025-9187? +

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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2025-9187? +

CVE-2025-9187 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.

What products are affected by CVE-2025-9187? +

CVE-2025-9187 affects products from mozilla, specifically: firefox, thunderbird. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-9187? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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