The ACEManager component of ALEOS 4.16 and earlier does not perform input sanitization during authentication, which could potentially result in a Denial of Service (DoS) condition for ACEManager without impairing other router functions. ACEManager recovers from the DoS condition by restarting within ten seconds of becoming unavailable.
https://www.forescout.com/resources/sierra21-vulnerabilities
https://lists.debian.org/debian-lts-announce/2023/12/msg00024.html