CVE-2020-5300

CVE-2020-5300 is a medium-severity vulnerability in Ory Hydra with a CVSS 3.x base score of 5.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-294.

Key facts

Description

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

Frequently asked questions

What is CVE-2020-5300?
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
How severe is CVE-2020-5300?
CVE-2020-5300 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2020-5300 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-5300?
CVE-2020-5300 affects Ory Hydra. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-5300?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-5300 published?
CVE-2020-5300 was published on 2020-04-06 and last updated on 2026-06-17.

References

Affected products (1)

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