# CVE-2026-40687

## Summary

- **CVE ID:** CVE-2026-40687
- **Severity:** MEDIUM
- **CVSS Score:** 4.8 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L)
- **CWE:** CWE-909
- **Published:** Apr 30, 2026
- **Last Modified:** May 1, 2026

## 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.

## Affected Products

- Exim — Exim (0)

## References

- [CNA](https://exim.org/static/doc/security/CVE-2025-40687.txt)
- [CNA](https://www.openwall.com/lists/oss-security/2026/04/30/21)
- [CNA](https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40687.assessment)
- [CNA](https://code.exim.org/exim/exim/commit/68b963b9f75ca27b38e1c0f8c87037990199f505)
- [CNA](https://exim.org/static/doc/security/CVE-2026-40687.txt)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.37%
- **EPSS Percentile:** 30.6

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._