CVE-2020-5300

What it is

In Hydra (an OAuth2 Server and OpenID Certified™ OpenID Connect Provider written in Go), before version 1.4.0+oryOS.17, when using client authentication method 'private_key_jwt' [1], OpenId specification says the following about assertion `jti`: "A unique identifier for the token, which can be used to prevent reuse of the token. These tokens MUST only be used once, unless conditions for reuse were negotiated between the parties". Hydra does not check the uniqueness of this `jti` value. Exploiting this vulnerability is somewhat difficult because: - TLS protects against MITM which makes it difficult to intercept valid tokens for replay attacks - The expiry time of the JWT gives only a short window of opportunity where it could be replayed This has been patched in version v1.4.0+oryOS.17

At a glance

Exploitability

Can be exploited over the network with a low-privilege account, but needs a user to act. High risk of data exposure.

Exploit odds

1.0% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2020-04-06 17:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 03:21 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.0% in the next 30 days (EPSS).
• Severity: 5.8 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2020-04-06 17:15 UTC

Last modified

2026-06-17 03:21 UTC

Exploit probability

1.0% · EPSS, next 30 days

Weakness

CWE-294

Record status

Modified

Affected

• Ory Hydra < 1.4.0

Attack profile CVSS 3.1 · 5.8

Attack vector

Network

Complexity

High

Privileges needed

Low

User interaction

Required

Scope

Changed

Confidentiality

High

Integrity

None

Availability

None

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-2020-5300.md and follow it. Check whether this project is affected by CVE-2020-5300. 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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