CVE-2026-45402

HIGHNVD 8.18.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.1 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 74% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
8.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, multiple endpoints accept a user-supplied file_id and attach the referenced file to a resource the caller controls (folder knowledge, knowledge-base contents) without verifying that the caller owns or has been granted access to the file. The file's content then becomes reachable through the downstream RAG / file-content paths, allowing any authenticated user to exfiltrate any other user's private file — and on the knowledge-base path, also to overwrite it — given knowledge of the file's UUID. This affects backend/open_webui/routers/folders.py (POST /api/v1/folders/{id}/update), backend/open_webui/routers/knowledge.py (add_file_to_knowledge_by_id), and backend/open_webui/routers/knowledge.py (add_files_to_knowledge_by_id_batch). This vulnerability is fixed in 0.9.5.

CVSS v3
8.1
EG Score
8.1(medium)
EPSS
26.7%
KEV
Not listed

Published

May 15, 2026

Last Modified

May 18, 2026

Advisory Details (1)

Auto-updated May 16, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Cross-User File Access via Unchecked file_id in Folder Knowledge and Knowledge-Base Attach Endpoints · Advisory · open-webui/open-webui · GitHub

https://github.com/open-webui/open-webui/security/advisories/GHSA-r472-mw7m-967f

Vendor Advisories for CVE-2026-45402(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
open-webui0.1.124 ... 0.9.4 (156 versions)0.9.5—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 6× in last 7d / 51× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 106 total refreshes for this CVE.

  1. 2026-07-11 08:27 UTCEPSS rescore
  2. 2026-07-09 19:10 UTCEPSS rescore
  3. 2026-07-08 15:16 UTCEPSS rescore
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  1. 2026-06-23 21:33 UTCEPSS rescore
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  27. 2026-06-11 21:27 UTCEG score recompute
  28. 2026-06-11 14:00 UTCEPSS rescore
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  34. 2026-06-10 08:55 UTCEG score recompute
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  40. 2026-06-08 08:01 UTCEG score recompute
  41. 2026-06-07 19:51 UTCEG score recompute
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  75. 2026-05-26 13:44 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-45402?
CVE-2026-45402 is a high vulnerability published on May 15, 2026. Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, multiple endpoints accept a user-supplied fileid and attach the referenced file to a resource the caller controls (folder knowledge, knowledge-base contents) without verifying that the…
When was CVE-2026-45402 disclosed?
CVE-2026-45402 was first published in the National Vulnerability Database on May 15, 2026, with the most recent update on May 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-45402 actively exploited?
CVE-2026-45402 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 26.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-45402?
CVE-2026-45402 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-45402?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45402, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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