ByteDance DeerFlow versions prior to commit 2176b2b contain a CWE-22 path traversal vulnerability in the bootstrap-mode custom-agent creation process. The agent name validation can be bypassed, allowing attackers to supply traversal-style or absolute path values. This influences directory creation and enables writing files outside the designated custom-agent directory, potentially resulting in arbitrary file write capabilities constrained by filesystem permissions. The vulnerability has a CVSS 4.0 base score of 7.1, reflecting a high severity level with network attack vector, low attack complexity, no privileges required, and no user interaction needed.

Successful exploitation allows an attacker with limited privileges to write arbitrary files outside the intended directory, potentially leading to unauthorized modification of system files or application data. The impact depends on the filesystem permissions of the affected system. There are no reports of active exploitation in the wild at this time.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict access to the affected system and monitor for suspicious activity related to custom-agent creation. Avoid running the vulnerable version in untrusted environments. Follow up with ByteDance for updates or patches addressing this vulnerability.