CVE-2026-56398Open WebUI - Stored Cross-Site Scripting via OAuth Picture Claim SVG Data URI

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.

8.5 HIGHEPSS 0.63%Not in KEVNVD: Analyzed

Last updated: 2026-07-16 20:03 UTC

OverviewCVSS details

8.5HIGHCVSS 4.0

Score source: VulnCheck (CNA)
NVD status: Analyzed
Published: Jul 15, 2026
Assigner: VulnCheck

Affected

open-webui (open-webui)

Versions: before 0.9.5
Fixed in: 0.9.5

Exploitation

Public exploit: Yes · 1 reference
CISA KEV: Not listed
KEV due date: —
SSVC: Exploitation none · Automatable no · Impact partial

EPSS · FIRST, scored Nov 8

0.63%chance of exploitation in 30 days

Higher than 50.68% of CVEs

CVSS 4.0 · VulnCheck (CNA)

8.5High

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Attack vector: Network
Attack complexity: Low
Attack requirements: None
Privileges required: Low
User interaction: Passive
Confidentiality impact: High
Integrity impact: High
Availability impact: None
Confidentiality (other systems): None
Integrity (other systems): None
Availability (other systems): None

CVSS 3.1 · NVD

9.0Critical

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: Required
Scope: Changed
Confidentiality impact: High
Integrity impact: High
Availability impact: High

CVSS 3.1 · VulnCheck (CNA)

7.3High

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: Required
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: None

NVD status: Analyzed

Overview Affected Products References

NVD CVE.org

Overview

Severity

Score	Severity	Version	Vector String
8.5	HIGH	4.0VulnCheck (CNA)	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
9.0	CRITICAL	3.1NVD	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
7.3	HIGH	3.1VulnCheck (CNA)	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

Details

CVE ID: CVE-2026-56398
Status: Analyzed
Assigner (CNA): VulnCheck
Published: Jul 15, 2026
Last modified: 2026-07-16 20:03 UTC
Weaknesses: CWE-20 · Improper Input Validation

Sources

Refreshed hourly from the sources above. Last fetched 2026-11-09 09:15 UTC.