The Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) 1.7 does not properly restrict the use of TGT credentials for armoring TGS requests, which might allow remote authenticated users to impersonate a client by rewriting an inner request, aka a "KrbFastReq forgery issue."

MIT Kerberos 5 (aka krb5) 1.3.x, 1.4.x, 1.5.x, 1.6.x, 1.7.x, and 1.8.x through 1.8.3 does not properly determine the acceptability of checksums, which might allow remote attackers to modify user-visible prompt text, modify a response to a Key Distribution Center (KDC), or forge a KRB-SAFE message via certain checksums that (1) are unkeyed or (2) use RC4 keys.

MIT Kerberos 5 (aka krb5) 1.8.x through 1.8.3 does not reject RC4 key-derivation checksums, which might allow remote authenticated users to forge a (1) AD-SIGNEDPATH or (2) AD-KDC-ISSUED signature, and possibly gain privileges, by leveraging the small key space that results from certain one-byte stream-cipher operations.

The merge_authdata function in kdc_authdata.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) 1.8.x before 1.8.4 does not properly manage an index into an authorization-data list, which allows remote attackers to cause a denial of service (daemon crash), or possibly obtain sensitive information, spoof authorization, or execute arbitrary code, via a TGS request that triggers an uninitialized pointer dereference, as demonstrated by a request from a Windows Active Directory client.

The kg_accept_krb5 function in krb5/accept_sec_context.c in the GSS-API library in MIT Kerberos 5 (aka krb5) through 1.7.1 and 1.8 before 1.8.2, as used in kadmind and other applications, does not properly check for invalid GSS-API tokens, which allows remote authenticated users to cause a denial of service (NULL pointer dereference and daemon crash) via an AP-REQ message in which the authenticator's checksum field is missing.

Double free vulnerability in do_tgs_req.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) 1.7.x and 1.8.x before 1.8.2 allows remote authenticated users to cause a denial of service (daemon crash) or possibly execute arbitrary code via a request associated with (1) renewal or (2) validation.

Use-after-free vulnerability in kadmin/server/server_stubs.c in kadmind in MIT Kerberos 5 (aka krb5) 1.5 through 1.6.3 allows remote authenticated users to cause a denial of service (daemon crash) via a request from a kadmin client that sends an invalid API version number.

The spnego_gss_accept_sec_context function in lib/gssapi/spnego/spnego_mech.c in the SPNEGO GSS-API functionality in MIT Kerberos 5 (aka krb5) 1.7 before 1.7.2 and 1.8 before 1.8.1 allows remote attackers to cause a denial of service (assertion failure and daemon crash) via an invalid packet that triggers incorrect preparation of an error token.

The Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) 1.7 before 1.7.2, and 1.8 alpha, allows remote attackers to cause a denial of service (assertion failure and daemon crash) via an invalid (1) AS-REQ or (2) TGS-REQ request.

Multiple integer underflows in the (1) AES and (2) RC4 decryption functionality in the crypto library in MIT Kerberos 5 (aka krb5) 1.3 through 1.6.3, and 1.7 before 1.7.1, allow remote attackers to cause a denial of service (daemon crash) or possibly execute arbitrary code by providing ciphertext with a length that is too short to be valid.