CVE-2026-56398

CRITICALNVD 9.09.0—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.0 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 66% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
9.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.0Exploit: None knownExposed: 0

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

Open WebUI before 0.9.5 contains a stored cross-site scripting vulnerability in the OAuth authentication flow where the picture claim URL MIME type is inferred from file extension rather than Content-Type header, allowing SVG files to bypass the profile image validator and be stored as data URIs. Authenticated users who visit the profile image endpoint receive attacker-controlled SVG content with inline disposition and no default security headers, enabling script execution in the same origin to steal authentication tokens and achieve account takeover.

CVSS v3
9.0
EG Score
9.0(medium)
EG Risk
41(Track)
EG Risk 41/100SSVC: 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 computed
Severity90% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
34%
KEV
Not listed

Published

July 15, 2026

Last Modified

July 16, 2026

Advisory Details (2)

Auto-updated Jul 15, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

Open WebUI - Stored Cross-Site Scripting via OAuth Picture Claim SVG Data URI | Advisories | VulnCheck

https://www.vulncheck.com/advisories/open-webui-stored-cross-site-scripting-via-oauth-picture-claim-svg-data-uri
github Patch Available🟡 PoC Available

Stored XSS via OAuth picture claim stored as SVG data URI in profile_image_url · Advisory · open-webui/open-webui · GitHub

https://github.com/open-webui/open-webui/security/advisories/GHSA-3wgj-c2hg-vm6q

Vendor Advisories for CVE-2026-56398(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 16× in last 7d / 27× 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.

  1. 2026-07-27 09:46 UTCGHSA enrichment
  2. 2026-07-27 06:05 UTCGHSA enrichment
  3. 2026-07-27 02:25 UTCGHSA enrichment
  4. 2026-07-26 22:42 UTCGHSA enrichment
  5. 2026-07-26 19:01 UTCGHSA enrichment
  6. 2026-07-26 15:20 UTCEG score recompute
  7. 2026-07-26 15:20 UTCGHSA enrichment
  8. 2026-07-26 14:54 UTCEPSS rescore
  9. 2026-07-26 11:38 UTCEG score recompute
  10. 2026-07-26 11:38 UTCGHSA enrichment
  11. 2026-07-25 14:18 UTCEPSS rescore
  12. 2026-07-24 14:18 UTCEPSS rescore
  13. 2026-07-23 14:18 UTCEPSS rescore
  14. 2026-07-23 03:20 UTCEG score recompute▲ 1.70
  15. 2026-07-22 14:08 UTCEPSS rescore
  16. 2026-07-20 17:08 UTCEPSS rescore
  17. 2026-07-19 14:31 UTCEPSS rescore
  18. 2026-07-19 14:31 UTCEPSS rescore
  19. 2026-07-19 02:29 UTCEPSS rescore
  20. 2026-07-18 10:04 UTCEPSS rescore
  21. 2026-07-16 20:26 UTCGHSA enrichment
  22. 2026-07-16 20:23 UTCNVD updateCVSS v3 → 9 · severity → CRITICAL
  23. 2026-07-16 17:03 UTCEPSS rescore
  24. 2026-07-16 09:36 UTCGHSA enrichment
  25. 2026-07-15 22:45 UTCGHSA enrichment
Show 2 more
  1. 2026-07-15 11:55 UTCEG score recompute
  2. 2026-07-15 11:54 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-56398?
CVE-2026-56398 is a critical vulnerability published on July 15, 2026. Open WebUI before 0.9.5 contains a stored cross-site scripting vulnerability in the OAuth authentication flow where the picture claim URL MIME type is inferred from file extension rather than Content-Type header, allowing SVG files to bypass the profile image validator and be stored as data URIs.…
When was CVE-2026-56398 disclosed?
CVE-2026-56398 was first published in the National Vulnerability Database on July 15, 2026, with the most recent update on July 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-56398 actively exploited?
CVE-2026-56398 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 65.9% of all scored CVEs.
What is the CVSS score of CVE-2026-56398?
CVE-2026-56398 has a CVSS v3 base score of 9.0 (NVD).
How do I remediate CVE-2026-56398?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56398, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-56398

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