CVE-2020-15234

6.1 MEDIUM 0.8% exploit odds Fix listed

What it is

ORY Fosite is a security first OAuth2 & OpenID Connect framework for Go. In Fosite before version 0.34.1, the OAuth 2.0 Client's registered redirect URLs and the redirect URL provided at the OAuth2 Authorization Endpoint where compared using strings.ToLower while they should have been compared with a simple string match. This allows an attacker to register a client with allowed redirect URL https://example.com/callback. Then perform an OAuth2 flow and requesting redirect URL https://example.com/CALLBACK. Instead of an error (invalid redirect URL), the browser is redirected to https://example.com/CALLBACK with a potentially successful OAuth2 response, depending on the state of the overall OAuth2 flow (the user might still deny the request for example). This vulnerability has been patched in ORY Fosite v0.34.1.

At a glance

Exploitability: Can be exploited over the network with an admin-level account, but needs a user to act. High risk of data exposure, data tampering.
Exploit odds: 0.8% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2020-10-02 21:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 02:56 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.8% in the next 30 days (EPSS).
Severity: 6.1 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2020-10-02 21:15 UTC
Last modified: 2026-06-17 02:56 UTC
Exploit probability: 0.8% · EPSS, next 30 days
Weakness: CWE-20 · Improper input validation
Record status: Modified

Affected

Ory Fosite < 0.34.1

Attack profile CVSS 3.1 · 6.1

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

Raw vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/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-2020-15234.md and follow it. Check whether this project is affected by CVE-2020-15234. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

· More options · Status badge

Download Square Reddit

Fix and advisories

References

NVD record · CVE.org record