CVE-2026-55486

9.3 CRITICAL 0.3% exploit odds Fix listed XSS Web app

What it is

The Goobi viewer is a web application that allows digitised material to be displayed in a web browser. From version 25.08 to before version 26.05, the IIIF Auth 2.0 endpoints auth/login and auth/token in AuthorizationFlowResource accept an origin query parameter without validation and then (1) embed it into the Content-Security-Policy: frame-ancestors response header and (2) embed it into an HTML response body as a JavaScript single-quoted postMessage argument. Because the attacker controls both the login and token calls that initiate the flow, the unescaped value yields reflected XSS. This issue has been patched in version 26.05.

At a glance

Exploitability: Can be exploited over the network without logging in, but needs a user to act. High risk of data exposure, data tampering.
Exploit odds: 0.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-06-16 22:28 UTC ReservedThe CVE id was reserved by its CNA
2026-10-23 15:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-30 16:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.3% in the next 30 days (EPSS).
Severity: 9.3 CRITICAL (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-10-23 15:17 UTC
Last modified: 2026-10-30 16:17 UTC
Exploit probability: 0.3% · EPSS, next 30 days
Weakness: CWE-79 · Cross-site scripting
Record status: Deferred

Attack profile CVSS 3.1 · 9.3

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Required
Scope: Changed
Confidentiality: High
Integrity: High
Availability: None

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-55486.md and follow it. Check whether this project is affected by CVE-2026-55486. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record