Time-of-check Time-of-use (TOCTOU) Race Condition in Open WebUI - CVE-2026-87996
Published: September 28, 2026
Vulnerability identifier: #VU152698
CSH Severity: Low
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-87996
CWE-ID: CWE-367
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to disclose sensitive information.
The vulnerability exists due to a time-of-check time-of-use race condition in SafePlaywrightURLLoader in backend/open_webui/retrieval/web/utils.py when processing user-submitted URLs. A remote user can submit a URL with DNS responses that alternate between public and internal addresses to disclose sensitive information.
Only deployments using the Playwright web loader with a browser able to reach internal addresses are affected.
Affected software
Open WebUI
How to mitigate CVE-2026-87996
Install security update from vendor's website.
Open WebUI - update to 0.11.1