The Heimdal Software Kerberos 5 implementation is vulnerable to a null pointer dereferance. An attacker with network access to an application that depends on the vulnerable code path can cause the application to crash.
The fix for CVE-2022-3437 included changing memcmp to be constant time and a workaround for a compiler bug by adding "!= 0" comparisons to the result of memcmp. When these patches were backported to the heimdal-7.7.1 and heimdal-7.8.0 branches (and possibly other branches) a logic inversion sneaked in causing the validation of message integrity codes in gssapi/arcfour to be inverted.
A heap-based buffer overflow vulnerability was found in Samba within the GSSAPI unwrap_des() and unwrap_des3() routines of Heimdal. The DES and Triple-DES decryption routines in the Heimdal GSSAPI library allow a length-limited write buffer overflow on malloc() allocated memory when presented with a maliciously small packet. This flaw allows a remote user to send specially crafted malicious data to the application, possibly resulting in a denial of service (DoS) attack.
Heimdal before 7.7.1 allows attackers to cause a NULL pointer dereference in a SPNEGO acceptor via a preferred_mech_type of GSS_C_NO_OID and a nonzero initial_response value to send_accept.
Heimdal before 7.7.1 allows remote attackers to execute arbitrary code because of an invalid free in the ASN.1 codec used by the Key Distribution Center (KDC).
PAC parsing in MIT Kerberos 5 (aka krb5) before 1.19.4 and 1.20.x before 1.20.1 has integer overflows that may lead to remote code execution (in KDC, kadmind, or a GSS or Kerberos application server) on 32-bit platforms (which have a resultant heap-based buffer overflow), and cause a denial of service on other platforms. This occurs in krb5_pac_parse in lib/krb5/krb/pac.c. Heimdal before 7.7.1 has "a similar bug."
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Heimdal is an implementation of ASN.1/DER, PKIX, and Kerberos. Versions prior to 7.7.1 are vulnerable to a denial of service vulnerability in Heimdal's PKI certificate validation library, affecting the KDC (via PKINIT) and kinit (via PKINIT), as well as any third-party applications using Heimdal's libhx509. Users should upgrade to Heimdal 7.7.1 or 7.8. There are no known workarounds for this issue.
A null pointer de-reference was found in the way samba kerberos server handled missing sname in TGS-REQ (Ticket Granting Server - Request). An authenticated user could use this flaw to crash the samba server.