CodexBar Privilege Escalation Vulnerability (CVE-2026-49134)

CodexBar versions prior to 0.32.0 are vulnerable to a privilege escalation vulnerability (CVE-2026-49134) in the CLI installer. A race condition exists in the temporary file handling. This flaw allows a local attacker with same-user privileges to execute arbitrary commands as root. The vulnerability occurs because the installer uses mktemp to create a temporary file, writes a privileged shell payload into it, and then executes the file with administrator privileges via bash. A local process can exploit this by rewriting the installer body before the administrator prompt is approved, leading to the execution of attacker-controlled commands with root privileges. This issue was reported on 2026-06-01 and affects versions prior to 0.32.0.

Attack Chain

1. A local attacker gains initial access to the system with limited privileges.
2. The attacker executes the vulnerable CodexBar CLI installer.
3. The installer creates a temporary file using mktemp to store a privileged shell payload.
4. The installer writes the privileged shell payload to the temporary file.
5. A race condition occurs where the attacker, using a separate local process, attempts to rewrite the installer body.
6. The attacker successfully overwrites the installer body with malicious code before the administrator prompt is approved.
7. The installer executes the modified (attacker-controlled) code with administrator privileges via bash.
8. The attacker gains root privileges and can execute arbitrary commands on the system.

Impact

Successful exploitation of this vulnerability allows a local attacker to escalate their privileges to root. This can lead to complete system compromise, including data theft, modification, and denial of service. The impact is severe, as it bypasses standard privilege separation mechanisms. The number of potential victims depends on the number of systems running vulnerable versions of CodexBar.

Recommendation

• Upgrade CodexBar to version 0.32.0 or later to remediate CVE-2026-49134.
• Monitor process creation events for execution of bash scripts from temporary directories, as demonstrated in the attack chain. Deploy the Sigma rule Detect Suspicious Bash Execution from Temp Directory to identify potential exploitation attempts.
• Implement file integrity monitoring to detect unauthorized modifications to the CodexBar installer binary, as described in the attack chain.