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CVE-2020-5300

Disallow replay of `private_key_jwt` by blacklisting JTIs in Hydra

Medium5.8EPSS 1.0%
Published
Updated
Reserved
Assigned by
GitHub_M

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

Scores

CVSS scores of CVE-2020-5300, by who scored it
Scored byCVSSScoreVector
GitHub_MCNA (assigner)3.1Medium5.8CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N
NVDNVD · Modified3.1Medium5.3CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
EPSS (exploitation in 30 days)
1.0% · top 36% of all CVEs (6 Nov 2026)
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The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.8.

Weakness

Affected products

Affected packages

From reviewed advisories of the GitHub Advisory Database.

References (3)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .