# CVE-2026-40686

> Vulnerability · severity: **LOW** (CVSS 3.7).

## Description

In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.

## Key facts

- **CVE ID:** CVE-2026-40686
- **Published:** 2026-04-30
- **CVSS severity:** LOW
- **CVSS base score:** 3.7
- **CWE codes:** CWE-125

## Affected products

- `exim:exim`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40686

## Citation

> AI Analytics. CVE-2026-40686. Retrieved 2026-07-02 from https://api.ai-analytics.org/cve/CVE-2026-40686. Derived from NIST NVD. Licensed CC0.

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