CVE-2026-3591

The record

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.

Affected packages

Related vulnerabilities

• CVE-2026-5950 An unbounded resend loop vulnerability exists in the BIND 9 resolver state machine during… Also affects bind
• CVE-2026-5947 Undefined behavior may result due to a race condition leading to a use-after-free… Also affects bind
• CVE-2026-5946 Multiple flaws have been identified in `named` related to the handling of DNS messages… Also affects bind
• CVE-2026-3039 BIND servers that are configured to use TKEY-based authentication via GSS-API tokens are… Also affects bind
• CVE-2026-3592 BIND resolvers are vulnerable to an amplified resource consumption/exhaustion attack. Also affects bind
• CVE-2026-3593 A use-after-free vulnerability exists within the DNS-over-HTTPS implementation. Also affects bind
• CVE-2026-3119 Under certain conditions, `named` may crash when processing a correctly signed query… Also affects bind
• CVE-2026-3104 A specially crafted domain can be used to cause a memory leak in a BIND resolver simply… Also affects bind