k5admind (kadmind) for Heimdal allows remote attackers to execute arbitrary code via a Kerberos 4 compatibility administration request whose framing length is less than 2, which leads to a heap-based buffer overflow.

Buffer overflow in libtelnet/encrypt.c in telnetd in FreeBSD 7.3 through 9.0, MIT Kerberos Version 5 Applications (aka krb5-appl) 1.0.2 and earlier, Heimdal 1.5.1 and earlier, GNU inetutils, and possibly other products allows remote attackers to execute arbitrary code via a long encryption key, as exploited in the wild in December 2011.

Last updated 24 July 2024

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.

In Heimdal through 7.4, remote unauthenticated attackers are able to crash the KDC by sending a crafted UDP packet containing empty data fields for client name or realm. The parser would unconditionally dereference NULL pointers in that case, leading to a segmentation fault. This is related to the kdcasrep function in kdc/kerberos5.c and the derlengthvisiblestring function in lib/asn1/derlength.c.

The transit path validation code in Heimdal before 7.3 might allow attackers to bypass the capath policy protection mechanism by leveraging failure to add the previous hop realm to the transit path of issued tickets.

In the client side of Heimdal before 7.6.0, failure to verify anonymous PKINIT PA-PKINIT-KX key exchange permits a man-in-the-middle attack. This issue is in krb5initcredsstep in lib/krb5/initcredspw.c.