{"id":"CVE-2026-45315","state":"PUBLISHED","title":"Open WebUI: Stored XSS via attacker-controlled file extension in /api/v1/audio/transcriptions","description":"Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, the audio transcription upload endpoint takes the file extension from the user-supplied filename and saves the file under CACHE_DIR/audio/transcriptions/.. The /cache/{path} route serves these files via FileResponse, which sets Content-Type from the on-disk extension and emits no Content-Disposition. A verified user with the default-on chat.stt permission can upload a polyglot WAV+HTML file named pwn.html and trick any other user into opening the resulting URL — the response comes back as text/html and any embedded <script> runs in the Open WebUI origin. This vulnerability is fixed in 0.9.3.","publishedAt":"2026-05-15T21:26:54.790Z","updatedAt":"2026-05-19T17:19:33.692Z","severity":{"score":8.7,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["open-webui open-webui"],"affected":[{"vendor":"open-webui","product":"open-webui","versions":[{"version":"< 0.9.3","status":"affected"}]}],"references":["https://github.com/open-webui/open-webui/security/advisories/GHSA-m8f9-9whg-f4xr"],"weaknesses":["CWE-79","CWE-434","CWE-646"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/45xxx/CVE-2026-45315.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-45315","state":"PUBLISHED","datePublished":"2026-05-15T21:26:54.790Z","dateUpdated":"2026-05-19T17:19:33.692Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-11T20:50:30.538Z"},"containers":{"cna":{"title":"Open WebUI: Stored XSS via attacker-controlled file extension in /api/v1/audio/transcriptions","descriptions":[{"lang":"en","value":"Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, the audio transcription upload endpoint takes the file extension from the user-supplied filename and saves the file under CACHE_DIR/audio/transcriptions/.. The /cache/{path} route serves these files via FileResponse, which sets Content-Type from the on-disk extension and emits no Content-Disposition. A verified user with the default-on chat.stt permission can upload a polyglot WAV+HTML file named pwn.html and trick any other user into opening the resulting URL — the response comes back as text/html and any embedded <script> runs in the Open WebUI origin. This vulnerability is fixed in 0.9.3."}],"affected":[{"vendor":"open-webui","product":"open-webui","versions":[{"version":"< 0.9.3","status":"affected"}]}],"references":[{"url":"https://github.com/open-webui/open-webui/security/advisories/GHSA-m8f9-9whg-f4xr","name":"https://github.com/open-webui/open-webui/security/advisories/GHSA-m8f9-9whg-f4xr","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":8.7,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"CHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-79","lang":"en","description":"CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-434","lang":"en","description":"CWE-434: Unrestricted Upload of File with Dangerous Type","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-646","lang":"en","description":"CWE-646: Reliance on File Name or Extension of Externally-Supplied File","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-05-15T21:26:54.790Z"},"source":{"advisory":"GHSA-m8f9-9whg-f4xr","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/open-webui/open-webui/security/advisories/GHSA-m8f9-9whg-f4xr","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-19T12:23:26.142818Z","id":"CVE-2026-45315","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-19T17:19:33.692Z"}}]}}}