Extremely large RSA keys in certificate chains can cause a client/server to expend significant CPU time verifying signatures. With fix, the size of RSA keys transmitted during handshakes is restricted to <= 8192 bits. Based on a survey of publicly trusted RSA keys, there are currently only three certificates in circulation with keys larger than this, and all three appear to be test certificates that are not actively deployed. It is possible there are larger keys in use in private PKIs, but we target the web PKI, so causing breakage here in the interests of increasing the default safety of users of crypto/tls seems reasonable.

Cargo downloads the Rust project’s dependencies and compiles the project. Cargo prior to version 0.72.2, bundled with Rust prior to version 1.71.1, did not respect the umask when extracting crate archives on UNIX-like systems. If the user downloaded a crate containing files writeable by any local user, another local user could exploit this to change the source code compiled and executed by the current user. To prevent existing cached extractions from being exploitable, the Cargo binary version 0.72.2 included in Rust 1.71.1 or later will purge caches generated by older Cargo versions automatically. As a workaround, configure one's system to prevent other local users from accessing the Cargo directory, usually located in `~/.cargo`.