{"id":"CVE-2026-40518","title":"ByteDance DeerFlow Path Traversal and Arbitrary File Write via Bootstrap Mode","summary":"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…","severity":"high","cvss":7.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H","cvssSource":"cna","cwe":["CWE-22"],"vendor":"bytedance","product":"deer-flow","affected":["deer-flow < 2176b2bbfccfce25ceee08318813f96d843a13fd"],"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-04-17T18:35:29.825676Z"},"exploitAvailable":true,"published":"2026-04-17","updated":"2026-11-08","sourceUpdated":"2026-11-08T14:02:56.489Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-40518","references":[{"url":"https://github.com/bytedance/deer-flow/pull/2274"},{"url":"https://github.com/bytedance/deer-flow/commit/2176b2bbfccfce25ceee08318813f96d843a13fd"},{"url":"https://www.vulncheck.com/advisories/bytedance-deerflow-path-traversal-and-arbitrary-file-write-via-bootstrap-mode"}],"tags":["cve.org","exploit-available"],"epss":0.00356,"epssPercentile":0.29549,"ingestedAt":"2026-11-08T14:51:22.440Z","slug":"CVE-2026-40518","body":"## Overview\n\nByteDance 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.\n\n## Affected\n\n- `deer-flow < 2176b2bbfccfce25ceee08318813f96d843a13fd`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":51,"depthScoreParts":{"impact":39.1,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[]}