CVE-2026-72888: Net::OAuth versions before 0.32 for Perl allow memory exhaustion via unbounded caching of failed module loads in smart_require

Net::OAuth versions before 0.32 for Perl allow memory exhaustion via unbounded caching of failed module loads in smartrequire.

smartrequire stores results in a process-global hash with no bound and no eviction, and keeps an entry for every class name it is asked about, including names that failed to load, because the return value of the failed eval is stored before the error is checked. The key comes off the wire on the server side: signaturemethodclass builds the class name from the signaturemethod parameter of the incoming message, and verify resolves it before any signature is checked.

A remote client chooses both how many entries are created and how long each key is. In a persistent server the hash grows for the life of the worker process until it exhausts memory. Header size limits bound the key length on the Authorization header path, but not on a POST body.