CVE-2025-47913: 
cAdvisor vulnerability analysis and mitigation

CVE-2025-47913 is a denial-of-service vulnerability in the golang.org/x/crypto/ssh/agent package that causes SSH clients to panic and terminate early when they receive an SSH_AGENT_SUCCESS message in response to a request expecting a typed (structured) response. The vulnerability affects all versions of golang.org/x/crypto/ssh/agent prior to 0.43.0 and was published on November 13, 2025. It carries a CVSS v3.1 base score of 7.5 (High) (GitHub Advisory, Microsoft MSRC). Downstream products from IBM (Watson Speech Services Cartridge, Storage Defender Copy Data Management, Guardium Data Security Center, Netezza Appliance, QRadar EDR, and EDB PGAI Hybrid Management) are also affected (Feedly).

The root cause is a reachable assertion (CWE-617) in the SSH agent client implementation within golang.org/x/crypto/ssh/agent. When the SSH agent client sends a request that expects a typed, structured response, it does not gracefully handle receiving an SSH_AGENT_SUCCESS message instead — a message type that carries no payload. This mismatch triggers a panic in the Go runtime, causing the client process to terminate abruptly. An unauthenticated network attacker can exploit this by acting as or compromising an SSH agent server and returning a malformed SSH_AGENT_SUCCESS response to a vulnerable client. The fix is tracked in Go change list go.dev/cl/700295 and issue go.dev/issue/75178 (GitHub Advisory, Go Vuln DB).

Successful exploitation causes the SSH client process to panic and terminate immediately, resulting in a complete loss of availability for that client session and any dependent operations. The impact is limited to availability — there is no confidentiality or integrity compromise. In environments where SSH agent forwarding is used for automated pipelines, remote management, or CI/CD workflows, repeated exploitation could disrupt critical infrastructure operations and remote access capabilities (Feedly, GitHub Advisory).

1. Reconnaissance: Identify applications or services using golang.org/x/crypto/ssh/agent versions prior to 0.43.0, including tools such as Portainer, Amazon SSM Agent, Podman, Buildah, rclone, or custom Go applications that use SSH agent forwarding.
2. Position as SSH agent server: Establish a position where the attacker controls or can intercept the SSH agent socket — for example, via a compromised host with agent forwarding enabled, a malicious SSH server, or a man-in-the-middle position on the agent socket.
3. Trigger the vulnerable code path: Wait for or induce the vulnerable SSH client to send a request to the agent that expects a typed (structured) response (e.g., a key list or sign request).
4. Send malformed SSH_AGENT_SUCCESS: Respond to the client's typed-response request with an SSH_AGENT_SUCCESS message (message type 6) instead of the expected typed response.
5. Client process crashes: The Go SSH agent client panics upon receiving the unexpected message type, causing the client process to terminate immediately, achieving denial of service (Go Issue, Go Vuln DB).

• Logs: Unexpected Go runtime panic stack traces in application logs referencing golang.org/x/crypto/ssh/agent; log entries showing abrupt SSH client process termination without a clean exit code.
• Process: SSH client or agent-dependent processes (e.g., ssm-agent, podman, buildah, custom Go binaries) terminating unexpectedly with a non-zero exit status or panic message.
• Network: Unusual or repeated SSH agent protocol messages on the agent socket (typically a Unix domain socket at $SSH_AUTH_SOCK) where SSH_AGENT_SUCCESS (0x06) is returned in response to requests expecting structured data.
• File System: Core dump files generated by Go runtime panics in directories associated with SSH-dependent services.

The primary remediation is to upgrade golang.org/x/crypto to version 0.43.0 or later, which contains the fix for this vulnerability (Go Vuln DB, Go CL). Downstream product users should apply vendor-specific patches: IBM has released advisories for Watson Speech Services Cartridge, Storage Defender Copy Data Management, Guardium Data Security Center, Netezza Appliance, QRadar EDR, and EDB PGAI Hybrid Management (IBM Advisory). Red Hat, SUSE, openSUSE, Fedora, Oracle, and Amazon Linux have also issued updates for affected packages such as Podman, Buildah, Amazon SSM Agent, and others. As a workaround where patching is not immediately possible, disable SSH agent forwarding and restrict access to SSH agent sockets to reduce exposure (Feedly).

The Go security team disclosed the vulnerability through the official Go vulnerability database and issued a patch promptly. IBM published multiple security bulletins acknowledging the impact on several of its enterprise products. The vulnerability received broad coverage across Linux distribution security channels (Red Hat, SUSE, Fedora, Oracle, openSUSE, Amazon Linux), reflecting its wide reach through the Go ecosystem. Community reaction has been measured, with no significant controversy or notable researcher commentary beyond standard patch advisories (IBM Advisory, Go Vuln DB).