GHSA-5pq9-5mpr-jj85MediumCVSS 5.3

Jervis Has a JWT Algorithm Confusion Vulnerability

Published
January 13, 2026
Last Modified
January 21, 2026

🔗 CVE IDs covered (1)

📋 Description

Vulnerability

https://github.com/samrocketman/jervis/blob/157d2b63ffa5c4bb1d8ee2254950fd2231de2b05/src/main/groovy/net/gleske/jervis/tools/SecurityIO.groovy#L244-L249

The code doesn't validate that the JWT header specifies "alg":"RS256".

Impact

Depending on the broader system, this could allow JWT forgery.

Internally this severity is low since JWT is only intended to interface with GitHub. External users should consider severity moderate.

Patches

Jervis patch will explicitly verify the algorithm in the header matches expectations and further verify the JWT structure.

Upgrade to Jervis 2.2.

Workarounds

External users should consider using an alternate JWT library or upgrade.

References

🎯 Affected products1

  • maven/net.gleske:jervis:< 2.2

🔗 References (6)