CVE-2024-49967 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
ext4: no need to continue when the number of entries is 1
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Analysis
by VulDB Data Team • 03/21/2026
The vulnerability in question relates to a potential denial of service condition within the ext4 filesystem implementation of the linux kernel. This issue manifests when processing directory entries where the system attempts to continue processing operations even when only a single entry remains, creating an unnecessary computational overhead and potentially leading to resource exhaustion scenarios. The flaw exists in how the filesystem handles directory traversal operations, specifically when dealing with edge cases involving minimal directory structures containing only one entry.
The technical root cause stems from improper conditional logic within the ext4 filesystem code where the system continues to execute processing loops or operations even when the entry count has been reduced to one. This condition violates fundamental principles of efficient resource management and can lead to unnecessary CPU cycles being consumed while maintaining redundant processing paths. The vulnerability demonstrates poor adherence to defensive programming practices and highlights issues in how the kernel handles boundary conditions within filesystem operations.
From an operational perspective, this vulnerability could enable a malicious actor to perform resource exhaustion attacks against systems running ext4 filesystems by crafting specific directory structures that trigger the unnecessary processing loop. The impact extends beyond simple performance degradation to potentially enabling denial of service conditions where legitimate system operations become starved of resources due to the inefficient handling of single-entry directories. This type of vulnerability aligns with common attack patterns identified in the attack tactic of privilege escalation and resource exhaustion as outlined in the mitre att&ck framework.
The fix for this vulnerability involves implementing proper early termination conditions within the directory processing code path, ensuring that when only a single entry remains, the system exits the processing loop rather than continuing with redundant operations. This approach aligns with established security best practices and follows the principle of least privilege by preventing unnecessary resource consumption. The solution directly addresses the underlying issue identified in common weakness enumeration cwe-691 which categorizes insecure coding practices that lead to excessive resource consumption.
Security practitioners should consider this vulnerability as part of broader filesystem hardening strategies, particularly when implementing security controls for systems handling sensitive data or operating in high-security environments where resource availability is critical. The fix demonstrates the importance of thorough code review processes and proper boundary condition testing within kernel-level components. Organizations utilizing ext4 filesystems should prioritize applying this patch to maintain system stability and prevent potential exploitation vectors that could lead to service disruption or unauthorized access attempts.