{"cve":"CVE-2026-87994","nvd":{"published":"2026-09-09T22:18:47.563","modified":"2026-09-16T15:15:32.030","status":"Analyzed","description":"Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.5 until 0.11.1, the channel branch of chat_completion in backend/open_webui/main.py checked channel write access and channel membership for a supplied message_id but did not verify that the calling user authored the targeted message. A channel member could use the chat completions endpoint to replace another member's message while preserving the victim as the stored author, altering the conversation record without gaining access to other channels. This issue is fixed in version 0.11.1.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","score":4.3},"cwes":["CWE-639","CWE-862"],"references":["https://github.com/open-webui/open-webui/commit/7d392bedc9c1aaecc94509a58e59186b614433dc","https://github.com/open-webui/open-webui/pull/28631","https://github.com/open-webui/open-webui/releases/tag/v0.11.1","https://github.com/open-webui/open-webui/security/advisories/GHSA-fmqh-xp37-5hr8","https://github.com/open-webui/open-webui/security/advisories/GHSA-fmqh-xp37-5hr8"],"products":["openwebui:open_webui"],"source":"nvd","synced_at":"2026-10-19T22:52:53.108888569+00:00"},"epss":{"cve":"CVE-2026-87994","score":0.00372,"percentile":0.31133,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-fmqh-xp37-5hr8","url":"https://osv.dev/vulnerability/GHSA-fmqh-xp37-5hr8","summary":"Open WebUI: Channel members can overwrite another member's message via the chat completions endpoint","modified":"2026-10-01T17:56:08.452057195Z","packages":[{"ecosystem":"PyPI","name":"open-webui","purl":"pkg:pypi/open-webui","ranges":[">=0.9.5 <0.11.1"],"fixed":["0.11.1"]}]},{"id":"PYSEC-2026-4122","url":"https://osv.dev/vulnerability/PYSEC-2026-4122","summary":"Open WebUI: Channel members can overwrite another member's message via the chat completions endpoint","modified":"2026-10-01T17:45:12.755347923Z","packages":[{"ecosystem":"PyPI","name":"open-webui","purl":"pkg:pypi/open-webui","ranges":[">=0.9.5 <0.11.1"],"fixed":["0.11.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}