CVE-2026-88000

Open WebUI: Any authenticated user can hang the server via message deletion in a cyclic chat tree

MEDIUM
6.5
CVSS Score
Published: September 9, 2026 at 09:35 PM UTC
Updated: September 14, 2026 at 06:04 PM UTC
1 product affected across 1 vendorOpen Webui

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.6%
SSVC
PoC

Description

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/chats/{id}/messages/{message_id} used the chat-history deletion helper in backend/open_webui/models/chats.py to follow childrenIds without recording visited message identifiers. An authenticated user could store a cyclic chat tree and delete a message, causing a synchronous infinite loop on the server request loop that blocked every user's requests until the process was killed. This issue is fixed in version 0.11.1.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.11.10.10.0 ≤ v < 0.11.1
Affected range stops below 0.11.1, so it looks safe — our inference, not a vendor statement

References (4)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/open-webui/open-webui/security/advisories/GHSA-3cgp-3cqx-j8w2
x_refsource_MISCExploitPatch
Source: cverecord
https://github.com/open-webui/open-webui/pull/28035
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/open-webui/open-webui/releases/tag/v0.11.1

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-835

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