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CVE-2026-45338 Openwebui CVE debrief

CVE-2026-45338 is a high-severity Server-Side Request Forgery (SSRF) issue in Open WebUI affecting versions before 0.9.0. According to the vendor advisory and NVD record, the flaw is in _process_picture_url() in backend/open_webui/utils/oauth.py, where URLs from OAuth picture claims are fetched without validate_url() being applied. That can let an attacker make the server request arbitrary internal or otherwise protected HTTP endpoints and return the full response content.

Vendor
Openwebui
Product
Open Webui
CVSS
HIGH 7.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-15
Original CVE updated
2026-05-18
Advisory published
2026-05-15
Advisory updated
2026-05-18

Who should care

Administrators and operators running self-hosted Open WebUI instances, especially those using OAuth-based login flows that process profile picture URLs. Security teams should also care if the deployment can reach internal services, metadata endpoints, or other sensitive network locations from the application host.

Technical summary

The vulnerability is an SSRF in the OAuth picture URL processing path. NVD records CVSS 3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N with a 7.7 HIGH score and CWE-918. The issue is described as fetching arbitrary URLs from OAuth picture claims without validate_url(), which permits server-originated HTTP requests to internal resources and exposure of the response body. The affected version range is all versions before 0.9.0, and the issue is fixed in 0.9.0.

Defensive priority

High. This is network-reachable, does not require user interaction, and can expose sensitive internal data from the Open WebUI server environment. Prioritize patching to 0.9.0 and validating whether the application host could access sensitive internal targets before remediation.

Recommended defensive actions

  • Upgrade Open WebUI to version 0.9.0 or later.
  • Review OAuth configurations and any features that ingest profile picture URLs or similar external URL claims.
  • Restrict outbound network access from the Open WebUI host to only required destinations, especially internal subnets and metadata services.
  • Monitor application and proxy logs for unexpected outbound requests originating from Open WebUI.
  • If patching is delayed, reduce exposure by disabling or limiting the relevant OAuth picture URL handling path where operationally feasible.

Evidence notes

The CVE record was published on 2026-05-15 and modified on 2026-05-18. The NVD record lists the vulnerability as analyzed, maps it to CWE-918, and shows the affected CPE range as open_webui versions before 0.9.0. The GitHub Security Advisory linked in NVD is the vendor reference used for mitigation context. The issue description supplied in the CVE data states that _process_picture_url() fetches arbitrary URLs from OAuth picture claims without validate_url(), enabling SSRF and response exfiltration.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-45338 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-45338

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

  • CVE-2026-45338 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-45338

    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.