{"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":"2026-08-12T03:51:21.967297485Z","published":"2026-03-24T12:49:16.276Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-22","CWE-284","CWE-73","CWE-94"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33309.json"},"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":"a47f2ad17eb662e940c550cfccb64a87dddd7e0b"}],"database_specific":{"cpe":"cpe:2.3:a:langflow:langflow:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"1.2.0"},{"fixed":"1.9.0"}],"source":["AFFECTED_FIELD","CPE_RANGE"]}}],"versions":["1.8.1","1.8.0.rc6","1.8.0.rc5","1.8.0.rc4","1.8.0.rc3","1.8.0.rc2","1.8.0.rc1","1.8.0.rc0","1.5.0.post1","1.4.2","1.4.1","1.4.0","1.3.4","1.3.3","1.3.2","1.3.1","1.3.0","1.2.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33309.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"}]}