bytedance deer-flow Directory Creation path traversal

Summaryinfo

A vulnerability has been found in bytedance deer-flow and classified as critical. Affected by this issue is some unknown functionality of the component Directory Creation Handler. Performing a manipulation results in path traversal. This vulnerability is known as CVE-2026-40518. Remote exploitation of the attack is possible. No exploit is available. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability, which was classified as critical, was found in bytedance deer-flow (the affected version unknown). This affects an unknown part of the component Directory Creation Handler. The manipulation with an unknown input leads to a path traversal vulnerability. CWE is classifying the issue as CWE-22. The product 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 product 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. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The weakness was published by Chia Min Jun Lennon. It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-40518 since 04/13/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1006 according to MITRE ATT&CK.

Applying the patch 2176b2bbfccfce25ceee08318813f96d843a13fd is able to eliminate this problem. The bugfix is ready for download at github.com.

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Productinfo

Vendor

• bytedance

Name

• deer-flow

License

• open-source

Website

• Product: https://github.com/bytedance/deer-flow/

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CPE 2.2info

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