What is CVE-2026-56854?

CVE-2026-56854 is a high-severity vulnerability in Golang.org/x/crypto Golang.org/x/crypto/ssh, classified under Incorrect Authorization. CVSS score: 7.5/10. Published 2026-08-28.

How severe is CVE-2026-56854?

High severity. CVSS v3 base score is 7.5 out of 10.

Auth bypass in Golang.org/x/crypto Golang.org/x/crypto/ssh

CVE-2026-56854

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.

Vulnerability class: Broken Access Control

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

Affected products

Golang.org/x/crypto Golang.org/x/crypto/ssh

Weakness classification (CWE)

CWE-863 — Incorrect Authorization

References

Frequently asked questions

What is CVE-2026-56854?: CVE-2026-56854 is a high-severity vulnerability in Golang.org/x/crypto Golang.org/x/crypto/ssh, classified under Incorrect Authorization. CVSS score: 7.5/10. Published 2026-08-28.
How severe is CVE-2026-56854?: High severity. CVSS v3 base score is 7.5 out of 10.