Multiple vulnerabilities were discovered in PyJWT affecting various Ubuntu LTS releases. These issues involve improper validation and handling of JWK keys, PEM representations, DER public keys, and redirects when fetching key sets. Exploitation could allow attackers to forge authentication tokens or cause sensitive information disclosure. The vulnerabilities affect Ubuntu 16.04 through 26.04 LTS versions. Fixes have been released in updated package versions for all affected Ubuntu releases.