by Kastro
Paper/Archive/CVE-2026-40687

CVE-2026-40687

Exim Exim — 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 t…

EPSS 0.4%CVSS 9.1
critical.is priorityof 100
34
CVSS 9.1 (NVD)9.1 / 10 × 3027.3Not in CISA KEV+300.0EPSS percentile 31.2.312 × 206.2No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Exim< 4.99.24.99.2CNA

Scores by source

NVD9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
mitre (CNA)4.8CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: partial

References

refopenwall.com/lists/oss-security/2026/04/30/21refexim.org/static/doc/security/cve-2026-04.1/CVE2026-40687.assessmentrefcode.exim.org/exim/exim/commit/68b963b9f75ca27b38e1c0f8c87037990199f505refexim.org/static/doc/security/CVE-2026-40687.txt