CVE-2026-45399

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, any authenticated user with low privileges can enumerate active background tasks across the system and stop tasks belonging to other users via the GET /api/tasks and POST /api/tasks/stop/{task_id} methods. This allows a casual user to disrupt system-wide chat usage by continuously canceling other users' active tasks. This is a real authorization vulnerability affecting integrity and usability in multi-user deployments. This vulnerability is fixed in 0.9.0.

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CVSS v3.1 Score

7.1

HIGH

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

EPSS — Exploit Prediction

0.0004

Probability of exploitation

0.14%

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-862 Missing Authorization

Affected Products

Vendor	Product	Versions
openwebui	open_webui	< 0.9.0

References

Advisories & Patches

https://github.com/open-webui/open-webui/security/advisories/GHSA-8jjp-r2w2-4v22 https://github.com/open-webui/open-webui/security/advisories/GHSA-8jjp-r2w2-4v22

Exploits

https://github.com/open-webui/open-webui/security/advisories/GHSA-8jjp-r2w2-4v22 https://github.com/open-webui/open-webui/security/advisories/GHSA-8jjp-r2w2-4v22

Frequently Asked Questions

What is CVE-2026-45399? +

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, any authenticated user with low privileges can enumerate active background tasks across the system and stop tasks belonging to other users via the GET /api/tasks and POST /api/tasks/stop/{task_id} methods. This allows a casual user to disrupt system-wide chat usage by continuously canceling other users' active tasks. This is a real authorization vulnerability affecting integrity and usability in multi-user deployments. This vulnerability is fixed in 0.9.0. It has a CVSS v3.1 base score of 7.1 (HIGH).

How severe is CVE-2026-45399? +

CVE-2026-45399 has a CVSS v3.1 score of 7.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0004, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-45399? +

CVE-2026-45399 affects products from openwebui, specifically: open_webui. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-45399? +

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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