Several vulnerabilities were discovered in Heimdal, an implementation of Kerberos 5 that aims to be compatible with MIT Kerberos. CVE-2021-3671 Joseph Sutton discovered that the Heimdal KDC does not validate that the server name in the TGS-REQ is present before dereferencing, which may result in denial of service. CVE-2021-44758 It was discovered that Heimdal is prone to a NULL dereference in acceptors where an initial SPNEGO token that has no acceptable mechanisms, which may result in denial of service for a server application that uses SPNEGO. CVE-2022-3437 Several buffer overflow flaws and non-constant time leaks were discovered when using 1DES, 3DES or RC4 . CVE-2022-41916 An out-of-bounds memory access was discovered when Heimdal normalizes Unicode, which may result in denial of service. CVE-2022-42898 It was discovered that integer overflows in PAC parsing may result in denial of service for Heimdal KDCs or possibly Heimdal servers. CVE-2022-44640 It was discovered that the Heimdal"s ASN.1 compiler generates code that allows specially crafted DER encodings to invoke an invalid free on the decoded structure upon decode error, which may result in remote code execution in the Heimdal KDC.