CVE-2026-40687

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 Vector

References

• https://code.exim.org/exim/exim/commit/68b963b9f75ca27b38e1c0f8c87037990199f505
• https://exim.org/static/doc/security/CVE-2026-40687.txt
• https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40687.assessment
• https://www.openwall.com/lists/oss-security/2026/04/30/21