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CVE-2026-45667 open-webui CVE debrief

Open WebUI versions prior to 0.8.0 expose an unauthenticated API endpoint (`GET /api/v1/memories/ef`) that triggers embedding generation through `request.app.state.EMBEDDING_FUNCTION(...)`. This allows any unauthenticated remote attacker to invoke embedding operations, which can result in direct financial cost exposure when configured with paid embedding providers. The vulnerability represents a missing authentication control (CWE-862) on a resource-intensive operation. The issue was disclosed publicly on 2026-05-15 and last modified on 2026-05-19. No known exploitation in ransomware campaigns has been reported.

Vendor
open-webui
Product
Unknown
CVSS
MEDIUM 6.5
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 Open WebUI instances prior to 0.8.0, particularly those using paid embedding providers or operating multi-tenant deployments where unauthenticated network access is possible. Security teams monitoring for API abuse and unexpected cloud service costs should prioritize this issue.

Technical summary

The `/api/v1/memories/ef` endpoint in Open WebUI prior to 0.8.0 lacks authentication requirements, permitting unauthenticated HTTP GET requests to trigger `EMBEDDING_FUNCTION` execution. This server-side function typically interfaces with external embedding providers (e.g., OpenAI, Azure, or self-hosted models with operational costs). Successful exploitation does not require user credentials or session tokens. The vulnerability is classified as CWE-862 (Missing Authorization) and carries a CVSS 3.1 score of 6.5 (MEDIUM) with vector AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L, indicating network accessibility, low attack complexity, no privilege requirements, and impacts to integrity and availability through resource consumption.

Defensive priority

medium

Recommended defensive actions

  • Upgrade Open WebUI to version 0.8.0 or later to remediate this vulnerability.
  • Review API access logs for unexpected `GET /api/v1/memories/ef` requests from unauthenticated sources, particularly those originating from external IP addresses.
  • If immediate patching is not feasible, implement network-level access controls (e.g., IP allowlisting, VPN requirements) to restrict access to the Open WebUI instance.
  • Audit embedding provider billing and usage dashboards for anomalous consumption patterns that may indicate exploitation.
  • Verify that authentication middleware is applied consistently across all API endpoints, especially those invoking external services with cost implications.

Evidence notes

CVE published 2026-05-15; modified 2026-05-19. Vendor advisory confirms authentication bypass on embedding function endpoint. CVSS 6.5 (MEDIUM) per NVD. CPE indicates affected versions: openwebui:open_webui versions prior to 0.8.0.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-45667 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-45667

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

  • CVE-2026-45667 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-45667

    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.