In MIT Kerberos 5 (aka krb5) before 1.22.3, there is a NULL pointer dereference if an application calls gssacceptseccontext() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, causing the process to terminate in parsenegomessage.

In MIT Kerberos 5 (aka krb5) before 1.21.3, an attacker can cause invalid memory reads during GSS message token handling by sending message tokens with invalid length fields.

In MIT Kerberos 5 (aka krb5) before 1.21.3, an attacker can modify the plaintext Extra Count field of a confidential GSS krb5 wrap token, causing the unwrapped token to appear truncated to the application.

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 krb5pacparse in lib/krb5/krb/pac.c. Heimdal before 7.7.1 has "a similar bug."

The Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.18.5 and 1.19.x before 1.19.3 has a NULL pointer dereference in kdc/dotgsreq.c via a FAST inner body that lacks a server field.

ecverify in kdc/kdcpreauthec.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.18.4 and 1.19.x before 1.19.2 allows remote attackers to cause a NULL pointer dereference and daemon crash. This occurs because a return value is not properly managed in a certain situation.

A flaw was found in krb5. MIT Kerberos 5 allows unbounded recursion via an ASN.1-encoded Kerberos message because the lib/krb5/asn.1/asn1encode.c support for BER indefinite lengths lacks a recursion limit.

MIT krb5 through 1.22.2 contains a NULL pointer dereference vulnerability in the KDC's getpacprincwithrealm() that returns success while leaving the client principal NULL on malformed names. A malicious or compromised cross-realm trusted KDC can send an S4U2Proxy request with a PAC carrying a malformed client name to crash krb5kdc and deny authentication.

MIT Kerberos 5 (krb5) through 1.22.2 contains a NULL pointer dereference in makecredlist() in rdcred.c that allows authenticated Kerberos clients to crash services by sending mismatched KRB-CRED arrays. Attackers can send forwarded credentials with more tickets than ticketinfo entries through gssacceptseccontext() to crash GSS-API acceptor services, causing denial of service.

A vulnerability in the MIT Kerberos implementation allows GSSAPI-protected messages using RC4-HMAC-MD5 to be spoofed due to weaknesses in the MD5 checksum design. If RC4 is preferred over stronger encryption types, an attacker could exploit MD5 collisions to forge message integrity codes. This may lead to unauthorized message tampering.

An integer underflow vulnerability was found in MIT krb5 in the berval2tldata() function in plugins/kdb/ldap/libkdbldap/ldapprincipal2.c. The function performs an unsigned subtraction (bvlen - 2) without a prior bounds check. When bvlen is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read.

The attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bvlen < 2, triggering the underflow when the KDC or kadmind reads principal data.

Upstream fix: https://github.com/krb5/krb5/commit/2a5fd83 MIT ticket: https://krbdev.mit.edu/rt/Ticket/Display.html?id=9206

An integer underflow vulnerability was found in MIT krb5 in the berval2tldata() function in plugins/kdb/ldap/libkdbldap/ldapprincipal2.c. The function performs an unsigned subtraction (bvlen - 2) without a prior bounds check. When bvlen is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read.

The attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bvlen < 2, triggering the underflow when the KDC or kadmind reads principal data.

Upstream fix: https://github.com/krb5/krb5/commit/2a5fd83 MIT ticket: https://krbdev.mit.edu/rt/Ticket/Display.html?id=9206

In MIT Kerberos 5 (aka krb5) before 1.22.3, there is an integer underflow and resultant out-of-bounds read if an application calls gssacceptseccontext() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, possibly causing the process to terminate in parsemessage.

In MIT Kerberos 5 (aka krb5) before 1.22.3, there is a NULL pointer dereference if an application calls gssacceptseccontext() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, causing the process to terminate in parsenegomessage.

In MIT Kerberos 5 (aka krb5) before 1.22.3, there is an integer underflow and resultant out-of-bounds read if an application calls gssacceptseccontext() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, possibly causing the process to terminate in parsemessage.

Under specific configurations where RC4-HMAC-MD5 is negotiated for GSSAPI-secured communication, attackers can sniff messages and use MD5 collision techniques to craft altered messages that retain the same MIC (Message Integrity Code). The vulnerable checksum function from RFC4757 allows this due to its flawed use of MD5. The attack relies on RC4 being chosen over stronger encryption options and presumes attacker access to the network traffic.

In MIT Kerberos 5 (aka krb5) before 1.21.3, an attacker can cause invalid memory reads during GSS message token handling by sending message tokens with invalid length fields.

Reference and upstream patch: https://github.com/krb5/krb5/commit/55fbf435edbe2e92dd8101669b1ce7144bc96fef

A flaw was found in MIT krb5 1.6 or later, an authenticated kadmin user with permission to add principals to an LDAP Kerberos database can circumvent a DN containership check by supplying both a "linkdn" and "containerdn" database argument, or by supplying a DN string which is a left extension of a container DN string but is not hierarchically within the container DN.

Reference: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=891869

Upstream patch: https://github.com/krb5/krb5/commit/e1caf6fb74981da62039846931ebdffed71309d1

A flaw was found in MIT krb5 1.6 or later, an authenticated kadmin user with permission to add principals to an LDAP Kerberos database can cause a null dereference in kadmind, or circumvent a DN container check, by supplying tagged data intended to be internal to the database module.

Reference: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=891869

Upstream patch: https://github.com/krb5/krb5/commit/e1caf6fb74981da62039846931ebdffed71309d1

An issue was discovered in MIT Kerberos 5 (aka krb5) through 1.16. The pre-defined function "strlen" is getting a "NULL" string as a parameter value in plugins/kdb/ldap/libkdbldap/ldapprincipal2.c in the Key Distribution Center (KDC), which allows remote authenticated users to cause a denial of service (NULL pointer dereference) via a modified kadmin client.

An issue was discovered in MIT Kerberos 5 (aka krb5) through 1.16. There is a variable "dbentry->nkeydata" in kadmin/dbutil/dump.c that can store 16-bit data but unknowingly the developer has assigned a "u4" variable to it, which is for 32-bit data. An attacker can use this vulnerability to affect other artifacts of the database as we know that a Kerberos database dump file contains trusted data.

An unspecified third-party database module for the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) 1.10.x allows remote authenticated users to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted request, a different vulnerability than CVE-2013-1418.

A null pointer dereference flaw was found in Kerberos's GSS-API spnego security mechanism implemenation. A local user could use this flaw to cause a denial of service (krb5 daemon crash) via invalid ContextFlags for the reqFlags field in the NegTokenInit (RFC 4178).

References: http://krbdev.mit.edu/rt/Ticket/Display.html?user=guest&pass=guest&id=6402

Upstream patch: http://src.mit.edu/fisheye/changelog/krb5/?cs=22099

Certain weaknesses in the implementation of version 4 of the Kerberos protocol (krb4) in the krb5 distribution, when triple-DES keys are used to key krb4 services, allow an attacker to create krb4 tickets for unauthorized principals using a cut-and-paste attack and "ticket splicing."

Version 4 of the Kerberos protocol (krb4), as used in Heimdal and other packages, allows an attacker to impersonate any principal in a realm via a chosen-plaintext attack.

The Key Distribution Center (KDC) in Kerberos 5 (krb5) 1.2.7 and earlier allows remote, authenticated attackers to cause a denial of service (crash) on KDCs within the same realm using a certain protocol request that causes the KDC to corrupt its heap (aka "buffer underrun").

The Key Distribution Center (KDC) in Kerberos 5 (krb5) 1.2.7 and earlier allows remote, authenticated attackers to cause a denial of service (crash) on KDCs within the same realm using a certain protocol request that causes an out-of-bounds read of an array (aka "array overrun").

Format string vulnerabilities in the logging routines for MIT Kerberos V5 Key Distribution Center (KDC) before 1.2.5 allow remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via format string specifiers in Kerberos principal names.

Unknown vulnerability in the chktrans.c of the libkrb5 library for MIT Kerberos V5 before 1.2.5 allows users from one realm to impersonate users in other realms that have the same inter-realm keys.

MIT Kerberos V5 Key Distribution Center (KDC) before 1.2.5 allows remote authenticated attackers to cause a denial of service (crash) on KDCs within the same realm via a certain protocol request that causes a null dereference.