golang.org/x/crypto/ssh/agent: SSH client panic due to unexpected SSH_AGENT_SUCCESS
CVE: CVE-2025-47913
Component: golang.org/x/crypto/ssh/agent
Severity: Important
CVSS v3: 7.5/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Release date: 2025-11-13T21:29:39.907000+00:00

A flaw in golang.org/x/crypto/ssh/agent causes the SSH agent client to panic when a peer responds with the generic SSH_AGENT_SUCCESS (0x06) message to requests expecting typed replies (e.g., List, Sign). The unmarshal layer produces an unexpected message type, which the client code does not handle, leading to panic("unreachable") or a nil-pointer dereference. A malicious agent or forwarded connection can exploit this to terminate the client process.

Statement: This vulnerability was marked as Important because it allows any malicious or misbehaving SSH agent to force a crash in the client process using a single valid protocol byte. The panic occurs before the client has a chance to validate message structure or recover, which means an attacker controlling—or intercepting—SSH agent traffic can reliably terminate processes that rely on agent interactions. In environments where SSH agents operate over forwarded sockets, shared workspaces, or CI/CD runners, this turns into a reliable, unauthenticated remote denial of service against critical automation or developer tooling. The flaw also stems from unsafe assumptions in the unmarshalling logic, where unexpected but protocol-legal message types drop into “unreachable” code paths instead of being handled gracefully—making it a design-level reliability break rather than a simple error-handling bug. For this reason, it is rated as an important availability-impacting vulnerability rather than a moderate issue.

Remediation:
Before applying this update, make sure all previously released errata relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

For supported configurations, refer to:

https://access.redhat.com/articles/1548993
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https://docs.redhat.com/en/documentation/red_hat_openshift_ai/
Before applying this update, make sure all previously released errata relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258
Before applying this update, make sure all previously released errata relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258
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The container images provided by this update can be downloaded from the Red Hat container registry at registry.redhat.io or registry.access.redhat.com using the 'podman pull' command.

For more information about the images, search the image name in the Red Hat Ecosystem Catalog.
The container images provided by this update can be downloaded from the Red Hat container registry at registry.redhat.io or registry.access.redhat.com using the 'podman pull' command.

For more information about the images, search the image name in the Red Hat Ecosystem Catalog.
Before applying this update, make sure all previously released errata relevant
to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258
Before applying this update, make sure all previously released errata relevant
to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11358
Before applying this update, make sure all previously released errata relevant
to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11458
Before applying this update, make sure all previously released errata relevant
to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258
Before applying this update, make sure all previously released errata relevant
to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258
Before applying this update, make sure all previously released errata relevant
to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258
Before applying this update, make sure all previously released errata relevant
to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258
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Platform Engineers, Software Developers and Security Professionals may use RHTAS to ensure the integrity, transparency and assurance of their organization's software supply chain.

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You can find the release notes for this version of Red Hat Trusted Artifact Signer at https://access.redhat.com/documentation/en-us/red_hat_trusted_artifact_signer/1.2/html-single/release_notes/index
Red Hat Trusted Artifact Signer simplifies cryptographic signing and verifying of software artifacts such as container images, binaries and source code changes. It is a self-managed on-premise deployment of the Sigstore project available at https://sigstore.dev

Platform Engineers, Software Developers and Security Professionals may use RHTAS to ensure the integrity, transparency and assurance of their organization's software supply chain.

For details on using the operator, refer to the product documentation at https://access.redhat.com/documentation/en-us/red_hat_trusted_artifact_signer/1.3

You can find the release notes for this version of Red Hat Trusted Artifact Signer at https://access.redhat.com/documentation/en-us/red_hat_trusted_artifact_signer/1.3/html-single/release_notes/index
No mitigation is currently available that meets Red Hat Product Security’s standards for usability, deployment, applicability, or stability.