What is CVE-2026-87998?
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.10.0 until 0.11.1, DELETE /api/v1/knowledge/{id}/delete in backend/open_webui/routers/knowledge.py authorized deletion against the knowledge base but then removed its administrator-owned external connection without a separate administrator check or a check for other dependent knowledge bases. A non-administrator with write access to one external knowledge base could delete shared instance configuration and make every other knowledge base using that connection unavailable. This issue is fixed in version 0.11.1.
The record classifies CVE-2026-87998 under weakness classes CWE-269, CWE-863. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction, and has high impact on integrity. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 26 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 7.1 — HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L - EPSS (FIRST)
- 0.2% probability of exploitation in the next 30 days, higher than 18.7% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 4.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-09-09, last modified 2026-09-10
Is CVE-2026-87998 being exploited?
It currently carries a trending score of 34 in the Threadlinqs vulnerability feed.
Affected products and versions
- open-webui: open-webui
How to fix CVE-2026-87998
No vendor patch reference has been recorded for CVE-2026-87998 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-87998
No threat campaign in the Threadlinqs corpus currently references CVE-2026-87998, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.