PatchSiren cyber security CVE debrief
CVE-2026-45385 open-webui CVE debrief
An Insecure Direct Object Reference (IDOR) vulnerability in Open WebUI's Channels feature allows any authenticated channel member to modify messages sent by other members, including administrators. The flaw exists in the `update_message_by_id` function, which only verifies channel membership via `is_user_channel_member` without checking message ownership. This affects group and direct message channels in versions prior to 0.9.5. The vulnerability was published on 2026-05-15 and last modified on 2026-05-19.
- Vendor
- open-webui
- Product
- Unknown
- CVSS
- MEDIUM 4.3
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-05-15
- Original CVE updated
- 2026-05-19
- Advisory published
- 2026-05-15
- Advisory updated
- 2026-05-19
Who should care
Organizations running self-hosted Open WebUI instances with the Channels feature enabled, particularly those using group channels for collaborative AI interactions or relying on message integrity for compliance or operational purposes.
Technical summary
The vulnerability stems from missing ownership verification in the message update workflow. When processing `update_message_by_id` requests for group or DM channels, the application validates that the requesting user is a channel member but fails to verify that the user owns the specific message being modified. This allows any authenticated member to craft API requests targeting arbitrary message IDs within shared channels, resulting in unauthorized message modification. The fix in version 0.9.5 adds proper message ownership validation to the authorization flow.
Defensive priority
medium
Recommended defensive actions
- Upgrade Open WebUI to version 0.9.5 or later to remediate this vulnerability
- Review channel message audit logs for unauthorized modifications if running affected versions
- Implement additional authorization checks in custom deployments if immediate patching is not feasible
- Monitor for anomalous message edit patterns in channel activity logs
Evidence notes
The vulnerability is documented in a GitHub Security Advisory (GHSA-wwhq-cx22-f7vv) with tags indicating exploit availability, mitigation guidance, and vendor advisory status. The NVD record confirms the affected CPE as `cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:*` with version end excluding 0.9.5. CVSS 3.1 vector: AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N. CWE-639 (Authorization Bypass Through User-Controlled Key) is identified as the weakness type.
Official resources
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CVE-2026-45385 CVE record
CVE.org
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CVE-2026-45385 NVD detail
NVD
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Source item URL
nvd_modified
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Mitigation or vendor reference
[email protected] - Exploit, Mitigation, Vendor Advisory
2026-05-15T21:16:36.907Z