- CVE-2018-5709: bounds-check key and name counts when loading a KDB dump - CVE-2020-28196: add recursion limit for ASN.1 indefinite lengths - CVE-2021-36222: fix KDC null deref on bad encrypted challenge - CVE-2022-42898: fix integer overflows in PAC parsing - CVE-2024-37370: verify the Extra Count field of CFX wrap tokens - CVE-2024-37371: reject GSS message tokens with invalid length fields - Bound dbentry->e_length when loading a KDB dump (upstream a9654198); the last unguarded 32-to-16-bit assignment in the function CVE-2018-5709 bounds - Validate the PAC length in mspac_internalize() (upstream 63ae6a8d); the serialized length reaching krb5_pac_parse() was unchecked. Adds the internal helper k5_ser_unpack_len to libkrb5.exports, as upstream does; no public interface changes - Carry the t_invalid.c regression tests from upstream 55fbf435, split across the CVE-2024-37370 and CVE-2024-37371 patches to match the code split. test_cfx_altered_ec is the case that fails without the 37370 fix and test_cfx_large_ec the one that fails without the 37371 fix; the other two carried cases do not discriminate on 1.17 and are noted as such in the patch headers. Test-only: no shipped binary changes