CVE-2026-40687

9.1 criticalEPSS 0.4%

Critical (9.1) in exim exim. EPSS 0.4% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

9.1 critical

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

EPSS: 0.4% chance of exploitation in the next 30 days; higher than 31% of CVEs (scores of 2026-10-31)
CWE: CWE-909
Published: 2026-04-30
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

exim:exim

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

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