CVE-2026-3591

Summary

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 Software

VendorProductVersion RangeStatus
ISCBIND 99.20.0 <= 9.20.20affected
ISCBIND 99.21.0 <= 9.21.19affected
ISCBIND 99.20.9-S1 <= 9.20.20-S1affected
ISCBIND 99.18.0 <= 9.18.46unaffected
ISCBIND 99.18.11-S1 <= 9.18.46-S1unaffected

Weaknesses

  • CWE-562: CWE-562 Return of Stack Variable Address
  • CWE-305: CWE-305 Authentication Bypass by Primary Weakness

Workarounds

No workarounds known.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References