Vulnerability Description
In Exim before 4.99.2, when the SPA authentication driver is used with an adversarial SPA resource, there can be an out-of-bounds write that crashes the connection instance, or erroneous data processing that divulges data from uninitialized heap memory.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Exim | Exim | < 4.99.2 |
Related Weaknesses (CWE)
References
- https://code.exim.org/exim/exim/commit/68b963b9f75ca27b38e1c0f8c87037990199f505Patch
- https://exim.org/static/doc/security/CVE-2026-40687.txtBroken Link
- https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40687.assessmentVendor Advisory
- https://www.openwall.com/lists/oss-security/2026/04/30/21Mailing ListThird Party Advisory
FAQ
What is CVE-2026-40687?
CVE-2026-40687 is a vulnerability with a CVSS score of 4.8 (MEDIUM). In Exim before 4.99.2, when the SPA authentication driver is used with an adversarial SPA resource, there can be an out-of-bounds write that crashes the connection instance, or erroneous data processi...
How severe is CVE-2026-40687?
CVE-2026-40687 has been rated MEDIUM with a CVSS base score of 4.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-40687?
Check the references section above for vendor advisories and patch information. Affected products include: Exim Exim.