What’s Vulnerable › Vulnerabilities

CVE-2026-59714: Open WebUI: Cross-channel message overwrite via chat completion API (single-model and multimodel message_ids)

• Severity: high (CVSS 7.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-13 · updated 2026-09-18
• Weakness: CWE-862

Description

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.5 before 0.10.0, any authenticated user can overwrite the content of a message in a channel they do not belong to (including private and DM channels) by sending a chat completion request with a channel:-prefixed chat_id and a target message_id. The channel: path routes pipeline output through _make_channel_emitter, which writes to the Messages table using the caller-supplied message_id without binding it to the channel. This issue is fixed in version 0.10.0.

Affected products

• open-webui: from 0.9.5, < 0.10.0

References

• https://github.com/open-webui/open-webui/commit/ac3449cac91e62b08a7c28e54fcd044d14dea791
• https://github.com/open-webui/open-webui/pull/26385
• https://github.com/open-webui/open-webui/releases/tag/v0.10.0
• https://github.com/open-webui/open-webui/security/advisories/GHSA-x2ff-v5v8-m75m

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