CVE-2024-39930 is a critical vulnerability identified in the built-in SSH server component of Gogs, a self-hosted Git service, affecting versions up to 0.13.0. The vulnerability stems from an argument injection flaw in the internal SSH handling code (internal/ssh/ssh.go), specifically related to the processing of environment variables passed via the --split-string parameter. Authenticated attackers who can establish an SSH connection to the Gogs server can exploit this flaw by sending a maliciously crafted environment request that injects arbitrary commands. This leads to remote code execution (RCE) on the host system, compromising confidentiality, integrity, and availability. The vulnerability is classified under CWE-88 (Argument Injection or Modification). The CVSS v3.1 base score is 9.9, reflecting the critical nature of the flaw with network attack vector, low attack complexity, no user interaction, and scope change. Notably, Windows installations of Gogs are unaffected due to differences in the SSH server implementation or environment handling. No official patches or fixes are linked yet, and no exploits have been observed in the wild, but the severity demands immediate attention. The vulnerability requires authentication, which somewhat limits exposure but still poses a significant risk in environments where user credentials may be compromised or where many users have SSH access.

The impact of CVE-2024-39930 is severe for organizations running Gogs with the built-in SSH server enabled on non-Windows platforms. Successful exploitation allows authenticated attackers to execute arbitrary code remotely, potentially leading to full system compromise, data theft, service disruption, or lateral movement within the network. This can undermine the integrity and availability of source code repositories and related infrastructure, causing operational downtime and reputational damage. Given the critical CVSS score and the nature of the vulnerability, attackers could leverage this flaw to implant backdoors, exfiltrate sensitive intellectual property, or disrupt development workflows. Organizations with weak authentication controls or exposed SSH access are at higher risk. The lack of user interaction and low attack complexity further increase the threat level. Although no exploits are currently known in the wild, the vulnerability's public disclosure may prompt rapid development of exploit code, increasing the urgency for mitigation.

To mitigate CVE-2024-39930, organizations should immediately disable the built-in SSH server in Gogs if it is not essential, especially on non-Windows systems. If SSH access is required, consider restricting it to trusted networks and enforcing strong authentication mechanisms such as multi-factor authentication and key-based authentication with strict key management. Monitor SSH logs for unusual environment variable requests or connection attempts. Apply any forthcoming official patches or updates from the Gogs project as soon as they become available. In the interim, consider deploying network-level controls such as firewall rules to limit SSH access and use intrusion detection/prevention systems to detect suspicious SSH environment variable usage. Conduct a thorough audit of user accounts with SSH access and revoke unnecessary privileges. Additionally, implement robust monitoring and incident response plans to quickly identify and respond to potential exploitation attempts. Regular backups and system integrity checks will help in recovery if compromise occurs.