CVE-2026-109295 (CVSS 6.5)

Description

Open WebUI from 0.11.0 before 0.11.4 contains a regular expression denial of service vulnerability that allows authenticated users to stall server workers via file search patterns. Attackers can instruct the model to call grep_knowledge_files or grep_chat_files with a catastrophically backtracking regex, blocking the event loop for two seconds per repeated call.

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CVSS v3.1 Score

6.5

MEDIUM

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

EPSS — Exploit Prediction

0.0031

Probability of exploitation

0.22%

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-1333 CWE-1333

References

Other References

https://github.com/open-webui/open-webui/security/advisories/GHSA-gfjp-5hc9-852r https://www.vulncheck.com/advisories/open-webui-0.11.0-before-0.11.4-redos-via-grep-knowledge-files-event-loop https://github.com/open-webui/open-webui/security/advisories/GHSA-gfjp-5hc9-852r

Frequently Asked Questions

What is CVE-2026-109295? +

Open WebUI from 0.11.0 before 0.11.4 contains a regular expression denial of service vulnerability that allows authenticated users to stall server workers via file search patterns. Attackers can instruct the model to call grep_knowledge_files or grep_chat_files with a catastrophically backtracking regex, blocking the event loop for two seconds per repeated call. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-109295? +

CVE-2026-109295 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0031, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-109295? +

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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