---
cve: "CVE-2026-40686"
severity: "LOW"
cvss: 3.7
epss: "25%"
vendor: "exim"
kev: false
exploited: false
published: "2026-04-30 22:16:25"
tags: [cve, security, low]
source: tsecurity.de CVE-Dossier
exported: "2026-09-15T14:07:42+02:00"
---

# CVE-2026-40686

> 3.7 LOW

## Beschreibung

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.

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Hoch | good |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Gering | warn |
| I Integrität | Keine | good |
| A Verfügbarkeit | Keine | good |

## Referenzen

- <https://www.openwall.com/lists/oss-security/2026/04/30/21>
- <https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40686.assessment>
- <https://code.exim.org/exim/exim/commit/f2570bde16fb4d4a1242ff363a4c4eecf6372efc>
- <https://exim.org/static/doc/security/CVE-2026-40686.txt>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-40686) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_