CVE-2026-56854: high-severity vulnerability in golang.org/x/crypto/ssh
Source-address critical option not enforced for non-public-key auth callbacks in golang.org/x/crypto/ssh
Published
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.4%
exploitation probability
0.4%top 62% of all CVEs
observed exploitation
nono source reports it
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.
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/sshRelated CVEs — golang.org/x/crypto/ssh
In the same product, most dangerous first.
CVE-2024-45337CRITICALMisuse of connection.serverAuthenticate may cause authorization bypass in golang.org/x/cryptoEPSS 3.2%CVE-2025-22869HIGHPotential denial of service in golang.org/x/cryptoEPSS 0.9%CVE-2026-39830CRITICALInvoking client can cause server deadlock on unexpected responses in golang.org/x/crypto/sshEPSS 0.7%CVE-2026-39834CRITICALInvoking infinite loop on large channel writes in golang.org/x/crypto/sshEPSS 0.6%CVE-2025-58181MEDIUMUnbounded memory consumption in golang.org/x/crypto/sshEPSS 0.6%CVE-2026-46595CRITICALInvoking VerifiedPublicKeyCallback permissions skip enforcement in golang.org/x/crypto/sshEPSS 0.6%