CVE-2025-67896: exim Heap Overflow — Fix

Description

Exim before 4.99.1, with certain non-default rate-limit configurations, allows a remote heap-based buffer overflow because database records are cast directly to internal structures without validation.

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CVSS v3.1 Score

7.0

HIGH

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

Weakness Type (CWE)

CWE-122 CWE-122

Affected Products

Vendor	Product	Versions
exim	exim	< 4.99.1

References

Advisories & Patches

https://exim.org/static/doc/security/ https://exim.org/static/doc/security/EXIM-Security-2025-12-09.1/report.txt

Other References

https://www.openwall.com/lists/oss-security/2025/12/11/2 http://www.openwall.com/lists/oss-security/2025/12/14/1 http://www.openwall.com/lists/oss-security/2025/12/18/3

Frequently Asked Questions

What is CVE-2025-67896? +

Exim before 4.99.1, with certain non-default rate-limit configurations, allows a remote heap-based buffer overflow because database records are cast directly to internal structures without validation. It has a CVSS v3.1 base score of 7.0 (HIGH).

How severe is CVE-2025-67896? +

CVE-2025-67896 has a CVSS v3.1 score of 7.0 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-67896? +

CVE-2025-67896 affects products from exim, specifically: exim. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-67896? +

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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CVE-2025-67896