---
cve: "CVE-2026-3591"
severity: "MEDIUM"
cvss: 5.4
epss: "0.4%"
vendor: "ISC"
kev: false
exploited: false
published: "2026-03-25 13:34:14"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-20T00:02:00+02:00"
---

# CVE-2026-3591

> 5.4 MEDIUM

## Beschreibung

A use-after-return vulnerability exists in the `named` server when handling DNS queries signed with SIG(0). Using a specially-crafted DNS request, an attacker may be able to cause an ACL to improperly (mis)match an IP address. In a default-allow ACL (denying only specific IP addresses), this may lead to unauthorized access. Default-deny ACLs should fail-secure.
This issue affects BIND 9 versions 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, and 9.20.9-S1 through 9.20.20-S1.
BIND 9 versions 9.18.0 through 9.18.46 and 9.18.11-S1 through 9.18.46-S1 are NOT affected.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- 12f97d4162d435940598de4870d0088b8e6d266c (Commit)
- 3e7037ceef40688d5b4eb4a55a9df80c7547dd9f (Commit)

## Referenzen

- <https://kb.isc.org/docs/cve-2026-3591>
- <https://downloads.isc.org/isc/bind9/9.20.21>
- <https://downloads.isc.org/isc/bind9/9.21.20>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-3591) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_