Medium

Jervis Has a JWT Algorithm Confusion Vulnerability

  • Disclosed: 13.01.2026
  • Updated: 11.10.2026 12:22

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 software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Java / Kotlin (Maven) net.gleske:jervis < 2.2 2.2

References

CVSS score 5.3/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness (CWE)
CWE-347
Platform
Java / Kotlin (Maven)
Package
net.gleske:jervis
Disclosed
13.01.2026
Updated
11.10.2026 12:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-5pq9-5mpr-jj85 - CC BY 4.0

Vulnerability history: net.gleske:jervis

All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries
7
First → latest
01.2026 01.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • High 6
  • Medium 1

Disclosures per year

  1. 2026: 7
  1. High · 7.5 CVE-2025-68931 < 2.2 2.2
  2. Jervis Has a JWT Algorithm Confusion Vulnerability this entry
    Medium · 5.3 CVE-2025-68925 < 2.2 2.2
  3. High · 5.9 CVE-2025-68704 < 2.2 2.2
  4. High · 7.5 CVE-2025-68703 < 2.2 2.2
  5. High · 7.5 CVE-2025-68702 < 2.2 2.2
  6. High · 7.5 CVE-2025-68701 < 2.2 2.2
  7. High · 7.5 CVE-2025-68698 < 2.2 2.2

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