CVE-2006-6128 in Linux
Summary
by MITRE
The ReiserFS functionality in Linux kernel 2.6.18, and possibly other versions, allows local users to cause a denial of service via a malformed ReiserFS file system that triggers memory corruption when a sync is performed.
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Analysis
by VulDB Data Team • 04/29/2026
The vulnerability described in CVE-2006-6128 represents a critical denial of service flaw within the Linux kernel's ReiserFS file system implementation. This issue specifically affects kernel versions up to and including 2.6.18, with potential impacts extending to other versions that share similar codebases. The vulnerability stems from inadequate input validation and memory management within the ReiserFS subsystem, creating a scenario where malformed file system structures can trigger catastrophic memory corruption during synchronization operations.
The technical flaw manifests when a local attacker constructs or manipulates a ReiserFS file system with specific malformed structures that, when processed during a sync operation, cause the kernel to attempt invalid memory accesses or corruption. This type of vulnerability falls under CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write conditions. The memory corruption occurs at the kernel level, bypassing normal user-space protections and directly affecting the kernel's memory management subsystem. When the sync operation is performed on the corrupted ReiserFS file system, the kernel's memory management routines encounter invalid pointers or corrupted data structures, leading to unpredictable behavior and ultimately system instability.
The operational impact of this vulnerability extends beyond simple denial of service to potentially compromising the entire system stability. Local users with access to the system can exploit this vulnerability to force kernel panics, system crashes, or complete system hangs that require manual intervention or system reboot to resolve. The attack vector is particularly concerning because it requires only local access and does not need network connectivity or elevated privileges beyond basic user accounts. This makes it a significant threat in multi-user environments where users might attempt to disrupt system operations or in scenarios where untrusted file systems are mounted automatically. The vulnerability affects systems that utilize ReiserFS as their primary or secondary file system, particularly those running older kernel versions that have not received security patches.
Mitigation strategies for CVE-2006-6128 require immediate kernel updates to versions that contain the necessary security patches addressing the memory corruption issues in the ReiserFS implementation. System administrators should prioritize patching affected systems, particularly those running kernel versions 2.6.18 or earlier, as the vulnerability has been well-documented and remediated in subsequent kernel releases. Additionally, organizations should implement monitoring solutions to detect unusual sync operations or file system errors that might indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under privilege escalation and denial of service tactics, as it allows local users to gain elevated system stability control through kernel-level memory corruption. Administrators should also consider disabling ReiserFS support in kernel configurations if the file system is not actively required, reducing the attack surface. Regular security audits and kernel version management practices should include verification of ReiserFS functionality and associated security patches to prevent similar vulnerabilities from persisting in production environments.