CVE-2010-0628 in Kerberos
Summary
by MITRE
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.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 05/03/2026
The vulnerability identified as CVE-2010-0628 represents a critical denial of service weakness within the SPNEGO GSS-API implementation of MIT Kerberos 5, affecting versions prior to 1.7.2 and 1.8.1. This flaw specifically targets the spnego_gss_accept_sec_context function located in lib/gssapi/spnego/spnego_mech.c, which serves as a crucial component in the authentication process for Kerberos-based systems. The vulnerability arises from inadequate input validation during the processing of SPNEGO packets, creating a scenario where malformed or invalid packets can trigger unexpected behavior in the authentication daemon.
The technical mechanism behind this vulnerability involves the improper handling of error tokens during the SPNEGO authentication negotiation process. When an attacker crafts a malicious packet that violates the expected SPNEGO protocol structure, the function fails to properly validate the incoming data before attempting to prepare an error token for transmission. This leads to an assertion failure within the Kerberos daemon, causing the process to terminate abruptly and resulting in a complete denial of service for legitimate authentication requests. The flaw operates at the protocol level, exploiting the lack of robust error handling in the GSS-API layer that sits between the application and the Kerberos authentication mechanisms.
The operational impact of CVE-2010-0628 extends beyond simple service disruption, as it can compromise the availability of authentication services critical to enterprise security infrastructure. Organizations relying on Kerberos for single sign-on, network authentication, and service access control face significant risk when exposed to this vulnerability, as attackers can systematically crash authentication daemons and prevent legitimate users from accessing protected resources. The vulnerability aligns with CWE-248, which addresses "Uncaught Exception" conditions in software systems, and demonstrates how improper exception handling in security-critical components can lead to complete service failures. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, representing "Network Denial of Service," where an adversary leverages software flaws to disrupt network services and authentication infrastructure.
Mitigation strategies for this vulnerability require immediate patching of affected Kerberos installations to versions 1.7.2 or 1.8.1, which contain the necessary fixes to properly validate SPNEGO packets and handle error conditions without crashing the daemon. System administrators should also implement network monitoring to detect anomalous SPNEGO packet patterns that might indicate exploitation attempts, while maintaining robust backup authentication mechanisms to ensure service continuity during remediation efforts. Additional defensive measures include configuring firewalls to limit SPNEGO traffic to trusted sources and implementing intrusion detection systems that can identify malformed GSS-API packets attempting to exploit this specific assertion failure condition.