Is CVE-2026-3591 actively exploited?

No active exploitation of CVE-2026-3591 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-3591 be exploited remotely?

Yes. CVE-2026-3591 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-3591?

CVE-2026-3591 has a CVSS score of 5.4 (MEDIUM).

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MEDIUM

CVE-2026-3591

CWE-305Published: March 25, 2026· Updated: Mar 25, 2026

5.4

CVSS v3.1

Official Description

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.

NVD Source

Technical Analysis

CVE-2026-3591 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.