Source-address critical option not enforced for non-public-key auth callbacks in golang.org/x/crypto/ssh (CVE-2026-56854) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-56854

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

Answer in brief

CVE-2026-56854 records a Unknown severity vulnerability in Source-address critical option not enforced for non-public-key auth callbacks in golang.org/x/crypto/ssh. The current sources do not mark it as known exploited. The current feed maps golang.org/x/crypto/golang.org/x/crypto/ssh (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 28, 2026Updated Aug 28, 2026Source checked Aug 28, 2026First seen by HOL Aug 28, 2026Material review Aug 28, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps golang.org/x/crypto/golang.org/x/crypto/ssh (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
golang.org/x/crypto/golang.org/x/crypto/sshgeneric	>=0 <0.55.0	0.55.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for golang.org/x/crypto/golang.org/x/crypto/ssh.
Review the reported fix. Update golang.org/x/crypto/golang.org/x/crypto/ssh to 0.55.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 28, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.