{"id":"CVE-2026-33309","summary":"Langflow has an Arbitrary File Write (RCE) via v2 API","details":"Langflow is a tool for building and deploying AI-powered agents and workflows. Versions 1.2.0 through 1.8.1 have a bypass of the patch for CVE-2025-68478 (External Control of File Name), leading to the root architectural issue within `LocalStorageService` remaining unresolved. Because the underlying storage layer lacks boundary containment checks, the system relies entirely on the HTTP-layer `ValidatedFileName` dependency. This defense-in-depth failure leaves the `POST /api/v2/files/` endpoint vulnerable to Arbitrary File Write. The multipart upload filename bypasses the path-parameter guard, allowing authenticated attackers to write files anywhere on the host system, leading to Remote Code Execution (RCE). Version 1.9.0 contains an updated fix.","aliases":["GHSA-g2j9-7rj2-gm6c","PYSEC-2026-79"],"modified":"2026-05-20T08:11:05.518860646Z","published":"2026-03-24T12:49:16.276Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33309.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-22","CWE-284","CWE-73","CWE-94"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33309.json"},{"type":"ADVISORY","url":"https://github.com/langflow-ai/langflow/security/advisories/GHSA-g2j9-7rj2-gm6c"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33309"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/langflow-ai/langflow","events":[{"introduced":"0134485d5d29e384ce6be42b9deef6b64ffe8f89"},{"fixed":"7f3b01629629d3229550259d2a969525b2a09391"}],"database_specific":{"versions":[{"introduced":"1.2.0"},{"fixed":"1.9.0"}]}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33309.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"}]}