An issue was discovered in phpseclib 1.x before 1.0.23, 2.x before 2.0.47, and 3.x before 3.0.36. When processing the ASN.1 object identifier of a certificate, a sub identifier may be provided that leads to a denial of service (CPU consumption for decodeOID).
https://lists.debian.org/debian-lts-announce/2024/03/msg00003.html
https://lists.debian.org/debian-lts-announce/2024/03/msg00002.html
https://gist.github.com/katzj/ee72f3c2a00590812b2ea3c0c8890e0b