CVE-2026-40518

EUVD-2026-23456

17.04.2026, 17:17

ByteDance DeerFlow before commit 2176b2b contains a path traversal and arbitrary file write vulnerability in bootstrap-mode custom-agent creation where the agent name validation is bypassed. Attackers can supply traversal-style values or absolute paths as the agent name to influence directory creation and write files outside the intended custom-agent directory, potentially achieving arbitrary file write on the system subject to filesystem permissions.

Path Traversal

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	Primary	7.1 HIGH	NETWORK	LOW	LOW	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H

Awaiting analysis

This vulnerability is currently awaiting analysis.

Base Score

CVSS 3.x

EPSS Score

Percentile: Unknown

Common Weakness Enumeration

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
The software uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the software does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

References

https://github.com/bytedance/deer-flow/commit/2176b2bbfccfce25ceee08318813f96d843a13fd

https://github.com/bytedance/deer-flow/pull/2274

https://www.vulncheck.com/advisories/bytedance-deerflow-path-traversal-and-arbitrary-file-write-via-bootstrap-mode