CVE-2026-54007

Open WebUI: Cross-origin postMessage confirmation bypass via action:submit

MEDIUM
6.5
CVSS Score
Published: June 23, 2026 at 04:51 PM UTC
Updated: June 27, 2026 at 11:42 AM UTC
1 product affected across 1 vendorOpen Webui

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.2%
SSVC
PoC

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6, the chat message listener allows non-same-origin input:prompt and action:submit messages, so an external site can set prompt text and trigger submitPrompt() in an authenticated victim session. I validated this with a cross-origin attacker page that auto-posted messages and caused unauthorized POST /api/v1/chats/new and POST /api/chat/completions requests containing attacker-controlled prompts. This enables cross-site forced actions and model/tool execution under victim privileges without consent. This vulnerability is fixed in 0.9.6.

Affected

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

v < 0.9.6
Affected range stops below 0.9.6, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/open-webui/open-webui/security/advisories/GHSA-3vv5-8xxp-4f55

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

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

CVSS

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

Quick Info

StatusMODIFIED
CWE
CWE-346

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