CVE-2026-56398: Open WebUI before 0.9.5 contains a stored cross-site scripting vulnerability in the OAuth authentication flow

Q: How do I fix CVE-2026-56398?

open webui: upgrade to 0.9.5. Exact commands for each OS are on this page.

Q: Is CVE-2026-56398 being exploited?

CVE-2026-56398 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-56398 affect?

CVE-2026-56398 affects open webui. Severity is high (CVSS 7.3). 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 bypas

Q: How urgent is CVE-2026-56398?

Priority 43/100. High severity; Public exploit reference

This month

HIGH 7.3UPGRADE

CVE-2026-56398 is a high-severity flaw (CVSS 7.3) affecting open webui. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	7.3 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.6% (top 50%)
CISA exploited list	No
Weakness	CWE-20
Published	2026-07-15
Last modified	2026-07-16

Publisher (CNA): VulnCheck · Vendor: openwebui

Last updated 2026-07-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-15 12:18 UTCPublished CVE record published
2026-07-16 20:03 UTCUpdated Record last modified

openwebui open webui UPGRADE

Affected: < 0.9.5

Fixed in: 0.9.5

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy open-webui || rpm -q open-webui || open-webui --version

2. UPGRADE to 0.9.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade open-webui

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade open-webui

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-56398?

open webui: upgrade to 0.9.5. Exact commands for each OS are on this page.

Is CVE-2026-56398 being exploited?

CVE-2026-56398 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-56398 affect?

CVE-2026-56398 affects open webui. Severity is high (CVSS 7.3). 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 bypas

How urgent is CVE-2026-56398?

Priority 43/100. High severity; Public exploit reference

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References

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