Back
CVE-2026-40518
ByteDance DeerFlow Path Traversal and Arbitrary File Write via Bootstrap Mode
High7.1EPSS 0.36%
- Published
- Updated
- Reserved
- Assigned by
- VulnCheck
Description
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| VulnCheckCNA (assigner) | 4.0 | High7.1 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N |
| VulnCheckCNA (assigner) | 3.1 | High7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H |
| NVDNVD · Analyzed | 4.0 | High7.1 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.36% · top 70% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.1.
Weakness
Affected products
References (3)
- https://github.com/bytedance/deer-flow/pull/2274 (opens in a new tab)issue-tracking
- https://github.com/bytedance/deer-flow/commit/2176b2bbfccfce25ceee08318813f96d843a13fd (opens in a new tab)patch
- https://www.vulncheck.com/advisories/bytedance-deerflow-path-traversal-and-arbitrary-file-write-via-bootstrap-mode (opens in a new tab)third-party-advisory
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-40518)Record last updated .