What is CVE-2024-45337?

Applications using crypto/ssh's ServerConfig.PublicKeyCallback may incorrectly authorize connections when the callback approves a key but authentication fails, due to a logic flaw in the authentication flow.

How do I fix CVE-2024-45337?

Upgrade Go to 1.22.10+ or 1.23.4+. Review your PublicKeyCallback implementation to ensure it rejects unauthorized keys. Add explicit key allowlist validation inside PublicKeyCallback. Rotate SSH host keys and audit SSH access logs for anomalies. Run static analysis (govulncheck) to detect usage of vulnerable patterns. Pin allowed public keys in your callback rather than relying on post-callback checks.

Which versions are affected by CVE-2024-45337?

Affected: Go < 1.22.10, < 1.23.4. Fixed in: Go 1.22.10+, 1.23.4+.

criticalCVSS 9.1/10·Published: 2024-12-11·Go standard library (crypto/ssh)

How to fix CVE-2024-45337 – Step-by-Step Guide

CVE-2024-45337 addresses a critical authentication bypass vulnerability in Go's `crypto/ssh` library. This flaw could allow unauthorized access to SSH servers built with affected Go versions. Immediate action is required to secure your applications.

CVE ID

CVE-2024-45337

Severity

CRITICAL

CVSS Score

9.1/10

Affected

Go standard library (crypto/ssh)

What is Go crypto/ssh – Misuse of ServerConfig.PublicKeyCallback?

This critical vulnerability, CVE-2024-45337, stems from a logic flaw in Go's `crypto/ssh` `ServerConfig.PublicKeyCallback`. Applications might incorrectly authorize SSH connections even if the `PublicKeyCallback` approves a key but subsequent authentication fails. This bypasses intended security checks, allowing unauthorized access.

Affected Versions

Go < 1.22.10, < 1.23.4

Fixed In

Go 1.22.10+, 1.23.4+

Official References

Impact and Risks for your Infrastructure

The impact of CVE-2024-45337 is severe: unauthorized SSH authentication bypass. Attackers can gain access to Go applications acting as SSH servers using any public key, potentially leading to full system compromise, data exfiltration, or service disruption. This poses a critical risk to infrastructure.

gosshauth-bypasscritical2024

Step-by-Step Mitigation Guide

To mitigate CVE-2024-45337, update your Go applications to versions 1.22.10+ or 1.23.4+. Recompile and redeploy your SSH server applications. Verify the fix by ensuring your `go.mod` reflects the updated Go version and conducting thorough authentication tests.

1Upgrade Go to 1.22.10+ or 1.23.4+.
2Review your PublicKeyCallback implementation to ensure it rejects unauthorized keys.
3Add explicit key allowlist validation inside PublicKeyCallback.
4Rotate SSH host keys and audit SSH access logs for anomalies.
5Run static analysis (govulncheck) to detect usage of vulnerable patterns.
6Pin allowed public keys in your callback rather than relying on post-callback checks.

Frequently Asked Questions

What is the CVSS score for CVE-2024-45337?▼

CVE-2024-45337 has a CVSS score of 9.1/10 (critical severity). This reflects the most severe potential impact, requiring immediate remediation.

Which versions of Go standard library (crypto/ssh) are affected?▼

Affected: Go < 1.22.10, < 1.23.4. The vulnerability was fixed in: Go 1.22.10+, 1.23.4+.

How long does it take to fix CVE-2024-45337?▼

For most teams: 15–60 minutes to apply the patch, plus 15 minutes of post-patch verification. Complex multi-service environments may require 2–4 hours including staging validation.

Is CVE-2024-45337 being actively exploited?▼

Check the NVD entry and CISA KEV catalog for exploitation status. As a critical-severity vulnerability, treat it as a priority remediation regardless of known exploitation status.

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This CVE fix guide is based on publicly available security advisories (NVD, vendor bulletins). Always test changes in a staging environment before applying to production. Verify against the official vendor advisory for the most up-to-date guidance.