CVE-2026-12490 PUBLISHED

Bypass of client certificate verification with transfer over TLS

Assigner: NLnet Labs
Reserved: 17.06.2026 Published: 25.06.2026 Updated: 25.06.2026

When a provide-xfr is given with a tls-auth-name, a secondary requesting a transfer should provide a client certificate with that name. However, no client certificate is needed when the request comes in over TLS over the regular tls-port (and not the tls-auth-port) or over over TCP over the regular port, when the other conditions of the provide-xfr rule match.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CVSS Score: 8.2

Transfer security restrictions for client certificates can be bypassed completely if the attacker can match the other access control conditions, and the tls-auth-xfr-only option is not explicitly set to yes (which it by default is not)

Product Status

Vendor NLnet Labs
Product NSD
Versions Default: unaffected
  • affected from 4.10.1 to 4.14.3 (excl.)

Solutions

This issue is fixed starting with version 4.14.3.

Credits

  • Qifan Zhang from Palo Alto Networks finder

References

Problem Types

  • CWE-306: Missing Authentication for Critical Function CWE
  • CWE-284: Improper Access Control CWE