Affected: lepture authlib

lepture Authlib before 1.3.1 has algorithm confusion with asymmetric public keys. Unless an algorithm is specified in a jwt.decode call, HMAC verification is allowed with any asymmetric public key. (This is similar to CVE-2022-29217 and CVE-2024-33663.)

Affected: Ubuntu:Pro:22.04:LTS: python-authlib, Ubuntu:Pro:24.04:LTS: python-authlib

Millie Solem discovered that Authlib did not properly restrict algorithm selection during JWT verification, allowing HMAC verification with asymmetric public keys when no algorithm was specified. A remote attacker could possibly use this issue to bypass signature verification and forge tokens, resulting in authentication bypass or privilege escalation. (CVE-2024-37568)

Muhammad Noman Ilyas discovered that Authlib did not properly enforce critical header parameter handling during JSON Web Signature verification, leading to unknown critical parameters being incorrectly accepted. A remote attacker could possibly use this issue to bypass security policies in mixed deployments, resulting in authentication bypass, replay attacks, or privilege escalation. (CVE-2025-59420)

Muhammad Noman Ilyas discovered that Authlib did not properly limit the size of JSON Web Signature or JSON Web Token header and signature segments. A remote attacker could possibly use this issue to cause excessive memory or processor consumption, leading to a denial of service. (CVE-2025-61920)

Muhammad Noman Ilyas discovered that Authlib performed unbounded decompression when processing certain compressed encrypted tokens. A remote attacker could possibly use this issue to send a specially crafted token that can be expanded to a large size during decompression, causing a denial of service. (CVE-2025-62706)

It was discovered that Authlib did not properly bind cached state information to the initiating user se…