CVE-2026-56854 PUBLISHED

Source-address critical option not enforced for non-public-key auth callbacks in golang.org/x/crypto/ssh

Assigner: Go
Reserved: 23.06.2026 Published: 28.08.2026 Updated: 28.08.2026

The source-address critical option in the Permissions returned by an authentication callback was only enforced for the PublicKeyCallback and VerifiedPublicKeyCallback paths, extending the fix for CVE-2026-46595. Permissions returned by the PasswordCallback, KeyboardInteractiveCallback, NoClientAuthCallback, and GSSAPIWithMICConfig.AllowLogin callbacks were not validated against the client's remote address, so a source-address restriction set by those callbacks was silently ignored. The check is now applied to the Permissions returned by any authentication callback.

Product Status

Vendor golang.org/x/crypto
Product golang.org/x/crypto/ssh
Versions Default: unaffected
  • affected from 0 to 0.55.0 (excl.)

Credits

  • Longwei Wang (@gn00295120)

References

Problem Types

  • CWE-863: Incorrect Authorization