Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to version 0.8.6, any authenticated user can overwrite any file's content by ID through the POST /api/v1/retrieval/process/files/batch endpoint. The endpoint performs no ownership check, so a regular user with read access to a shared knowledge base can obtain file UUIDs via GET /api/v1/knowledge/{id}/files and then overwrite those files, escalating from read to write. The overwritten content is served to the LLM via RAG, meaning the attacker controls what the model tells other users. Version 0.8.6 patches the issue.
CVE-2026-28788
HIGHPre-NVD 7.17.1
EchelonGraph scoreLOW confidence
This high-severity CVE scores 7.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: secondary
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 3%CVSS: 7.1Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.1
- EG Score
- 7.1(low)
- EG Risk
- 36(Track)EG Risk 36/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity71% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 3%
- EPSS %ILE
- 85%
- KEV
- Not listed
Published
March 27, 2026
Last Modified
June 17, 2026
References (1)
- security-advisories@githubhttps://github.com/open-webui/open-webui/security/advisories/GHSA-jjp7-g2jw-wh3j
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 2× in last 7d / 2× 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.
- 2026-07-28 15:36 UTCEPSS rescore
- 2026-07-27 14:20 UTCEG score recompute
Related CVEs(same CWE)
Same CWE
10 shownCWE-639
- CVE-2018-25270EG 9.8CRITICAL
- CVE-2017-20223EG 9.8CRITICAL
- CVE-2019-25487EG 9.8EPSS p94CRITICAL
- CVE-2019-25235EG 9.8CRITICAL
- CVE-2019-15310EG 9.8EPSS p94CRITICAL
- CVE-2019-15913EG 9.8CRITICAL
- CVE-2019-16340EG 9.8EPSS p97CRITICAL
- CVE-2019-13360EG 9.8EPSS p98CRITICAL
- CVE-2019-12866EG 9.8CRITICAL
- CVE-2019-9756EG 9.8CRITICAL
Frequently asked(5)
What is CVE-2026-28788?
CVE-2026-28788 is a high vulnerability published on March 27, 2026. Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to version 0.8.6, any authenticated user can overwrite any file's content by ID through the POST /api/v1/retrieval/process/files/batch endpoint. The endpoint performs no ownership check, so a…
When was CVE-2026-28788 disclosed?
CVE-2026-28788 was first published in the National Vulnerability Database on March 27, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-28788 actively exploited?
CVE-2026-28788 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3% probability of exploitation in the next 30 days, which ranks it in the top 14.7% of all scored CVEs.
What is the CVSS score of CVE-2026-28788?
CVE-2026-28788 has a CVSS v3 base score of 7.1 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-28788?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-28788, 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.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-28788
Is Your Infrastructure Affected by CVE-2026-28788?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.