CVE-2026-54020

EUVD-2026-52900
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. Prior to 0.11.0, Open WebUI resolved a hostname during URL validation and rejected private, loopback, and link-local addresses, but the HTTP clients resolved the hostname again at connection time. An authenticated attacker who controlled authoritative DNS for a submitted hostname could answer with a public address during validation and an internal one during connection, reaching cloud metadata, loopback admin APIs, or internal services through URL ingest, chat image_url fetches, image editing, or OAuth profile-picture fetches, with most paths returning the response to the attacker and the OAuth path forwarding the OAuth access token. This issue is fixed in 0.11.0.
TOCTOU
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
6.3 MEDIUM
NETWORK
HIGH
LOW
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N