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PatchSiren cyber security CVE debrief

CVE-2026-44558 open-webui CVE debrief

A missing authorization check in Open WebUI's channel router allows non-admin users to bypass access controls. Prior to version 0.9.0, the create and update paths for group channels fail to invoke `filter_allowed_access_grants`, permitting users with channel creation or ownership privileges to submit arbitrary access grants—including public wildcard grants—without administrative validation. This enables unauthorized broadening of channel visibility beyond intended permissions. The vulnerability is classified as CWE-862 (Missing Authorization) and carries a CVSS 3.1 score of 5.4 (Medium). The issue was published on 2026-05-15 and last modified on 2026-05-19. Open WebUI version 0.9.0 contains the fix.

Vendor
open-webui
Product
Unknown
CVSS
MEDIUM 5.4
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 multi-user deployments, particularly those relying on group-based access controls for sensitive AI conversations.

Technical summary

The Open WebUI channel router's create and update endpoints omit a critical `filter_allowed_access_grants` call, enabling privilege escalation where non-administrative users can define unrestricted public access to group channels they create or own.

Defensive priority

medium

Recommended defensive actions

  • Upgrade Open WebUI to version 0.9.0 or later to obtain the authorization fix.
  • Review existing group channel access grants for unauthorized public wildcard entries created prior to patching.
  • Audit user permissions to ensure only trusted administrators possess channel creation and ownership capabilities.
  • Monitor application logs for suspicious channel creation or access grant modification activity.

Evidence notes

The CVE description and NVD metadata confirm the vulnerable component is the channel router in Open WebUI versions prior to 0.9.0. The GitHub Security Advisory (GHSA-7rjh-px4v-5w55) is cited as both exploit source and vendor advisory. CVSS vector AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N supports network attack with low privileges required.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-44558 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-44558

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-44558 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-44558

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.