Amazon Linux 2023: CVE-2023-29409: Medium priority package update for amazon-cloudwatch-agent (Multiple Advisories)

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.
A denial of service vulnerability was found in the Golang Go package caused by an uncontrolled resource consumption flaw. By persuading a victim to use a specially crafted certificate with large RSA keys, a remote attacker can cause a client/server to expend significant CPU time verifying signatures, resulting in a denial of service condition.