CVE-2026-40518

HIGH 7.1

ByteDance DeerFlow Path Traversal and Arbitrary File Write via Bootstrap Mode

CVSS Score

7.1

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-22
Vendor	bytedance
Product	deer-flow
Published	Apr 17, 2026
Last Updated	Apr 17, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

High

Affected Versions

bytedance / deer-flow

0 < 2176b2bbfccfce25ceee08318813f96d843a13fd

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/bytedance/deer-flow/pull/2274 github.com: https://github.com/bytedance/deer-flow/commit/2176b2bbfccfce25ceee08318813f96d843a13fd vulncheck.com: https://www.vulncheck.com/advisories/bytedance-deerflow-path-traversal-and-arbitrary-file-write-via-bootstrap-mode

Credits

Chia Min Jun Lennon