CVE-2025-15661

A flaw in libssh2's sftp_symlink() function allows a malicious SSH server or man-in-the-middle attacker to trigger an out-of-bounds heap read via a crafted SSH_FXP_NAME response. This can disclose heap memory contents or crash the application, causing a denial of service (DoS).

This Moderate-impact out-of-bounds heap read flaw in libssh2 allows a malicious SSH server or man-in-the-middle attacker to crash the application (DoS) or disclose heap memory by sending a crafted SFTP response.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Implement strict network egress filtering to allow outbound SSH/SFTP traffic only to known, trusted endpoints. Additionally, enforce strict SSH host key checking in your libssh2 client applications to reject unknown servers and prevent Man-in-the-Middle (MitM) attacks.