CVE-2006-5483 in FreeBSD
Summary
by MITRE
p1003_1b.c in FreeBSD 6.1 allows local users to cause an unspecified denial of service by setting a scheduler policy, which should only be settable by root.
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Analysis
by VulDB Data Team • 04/25/2026
The vulnerability described in CVE-2006-5483 affects FreeBSD 6.1 systems and relates to improper privilege escalation within the POSIX scheduling policy implementation. This issue resides in the p1003_1b.c source file which handles POSIX thread scheduling attributes and policies. The flaw allows local unprivileged users to manipulate scheduler policies that should be restricted to root-level privileges only, creating a potential pathway for privilege escalation attacks. The vulnerability specifically targets the pthread_setschedparam and related scheduling functions that govern thread execution priorities and scheduling algorithms within the operating system's threading subsystem.
The technical implementation of this vulnerability stems from inadequate access control checks within the kernel's POSIX scheduling interface. When local users invoke scheduling policy functions without proper privilege verification, the system fails to validate whether the calling process possesses sufficient privileges to modify these critical system parameters. This represents a classic case of insufficient privilege checking that violates fundamental security principles. The flaw operates at the kernel level where scheduling policies are enforced, making it particularly dangerous as it can be exploited to manipulate thread execution behavior and potentially disrupt system stability. According to CWE classification, this maps to CWE-276: Improper Privilege Management, which encompasses issues where programs or processes fail to properly enforce access control mechanisms.
The operational impact of this vulnerability extends beyond simple denial of service scenarios. While the description mentions unspecified denial of service, the underlying privilege escalation capability presents broader security implications including potential system compromise. Local attackers could leverage this vulnerability to gain elevated privileges, potentially leading to complete system control. The vulnerability affects systems running FreeBSD 6.1 and likely impacts other POSIX-compliant systems with similar implementations. From an attacker's perspective, this represents a low-effort privilege escalation vector that could be combined with other techniques to establish persistent access or conduct more sophisticated attacks. The vulnerability's exploitation does not require network access, making it particularly concerning for systems where local user access cannot be fully controlled.
Mitigation strategies for this vulnerability should focus on immediate system updates and access control hardening. The primary remediation involves applying the official FreeBSD security patch that addresses the privilege checking issue in the p1003_1b.c file. System administrators should also implement comprehensive monitoring for unauthorized scheduling policy modifications and establish strict access controls for system resources. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically T1068: Exploitation for Privilege Escalation, where adversaries leverage system weaknesses to gain elevated privileges. Additional defensive measures include implementing mandatory access controls, restricting local user privileges through proper account management, and conducting regular security audits of system calls and privilege boundaries. Organizations should also consider deploying intrusion detection systems that can monitor for suspicious scheduling policy changes and maintain up-to-date vulnerability assessments to prevent similar issues in other system components.