CVE-2026-87997: Auth Bypass (CVSS 4.3)

Description

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.10.0 until 0.11.1, POST /api/chat/completions and POST /api/v1/chat/completions in backend/open_webui/main.py copied a client-supplied folder_id into a new chat without applying the folder write-access check used by the dedicated chat routes. An authenticated user who knew a shared folder identifier could inject an attacker-controlled chat into a folder where the user had read-only or no write access, causing the entry to appear to authorized folder readers. This issue is fixed in version 0.11.1.

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CVSS v3.1 Score

4.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS — Exploit Prediction

0.0021

Probability of exploitation

0.12%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-639 CWE-639

CWE-862 Missing Authorization

References

Other References

https://github.com/open-webui/open-webui/commit/d9e23b90c100d19b00270aea3cde0501d2354a6c https://github.com/open-webui/open-webui/pull/28366 https://github.com/open-webui/open-webui/releases/tag/v0.11.1 https://github.com/open-webui/open-webui/security/advisories/GHSA-3pf7-q2g3-wj28 https://github.com/open-webui/open-webui/security/advisories/GHSA-3pf7-q2g3-wj28

Frequently Asked Questions

What is CVE-2026-87997? +

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.10.0 until 0.11.1, POST /api/chat/completions and POST /api/v1/chat/completions in backend/open_webui/main.py copied a client-supplied folder_id into a new chat without applying the folder write-access check used by the dedicated chat routes. An authenticated user who knew a shared folder identifier could inject an attacker-controlled chat into a folder where the user had read-only or no write access, causing the entry to appear to authorized folder readers. This issue is fixed in version 0.11.1. It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2026-87997? +

CVE-2026-87997 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0021, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-87997? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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