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The vulnerability in the `golang.org/x/crypto/ssh/agent` package stems from inadequate validation of message sizes during the processing of new identity requests. Specifically, the agent server fails to properly check the length of incoming messages before attempting to parse them. When a maliciously crafted, short message is received, the parsing logic performs an out-of-bounds read by accessing memory beyond the actual message buffer. In the Go runtime, this attempt to read beyond a slice’s boundaries triggers a panic, causing the SSH agent process to crash. This denial-of-service condition can be exploited by any client able to send a malformed request to the agent’s socket.
Platform: Golang crypto/ssh/agent
Version: pre-fix
Vulnerability: Out-of-bounds read
Severity: Moderate
date: 2025-11-19
Prediction: 2025-12-10
What Undercode Say:
Check if your Go project uses the vulnerable package golang.org/x/crypto/ssh/agent
// Code snippet showing the vulnerable pattern (conceptual)
func (s server) processRequest(data []byte) {
// ... logic to handle message type ...
if msgType == addIdentityMsg {
// Missing check for len(data) before parsing
key, err := parseKey(data[1:]) // Potential out-of-bounds read if data is too short
}
}
How Exploit:
An attacker sends a specially crafted, truncated network message to the SSH agent’s listening socket, triggering a panic and crashing the agent process.
Protection from this CVE:
Update the `golang.org/x/crypto/ssh/agent` package to the patched version once released. Apply input validation for message size.
Impact:
Denial-of-Service (DoS) via SSH agent crash, disrupting SSH key operations.
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Sources:
Reported By: github.com
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