CVE-2014-0100 in Linux
Summary
by MITRE • 01/25/2023
Race condition in the inet_frag_intern function in net/ipv4/inet_fragment.c in the Linux kernel through 3.13.6 allows remote attackers to cause a denial of service (use-after-free error) or possibly have unspecified other impact via a large series of fragmented ICMP Echo Request packets to a system with a heavy CPU load.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 05/07/2026
The vulnerability identified as CVE-2014-0100 represents a critical race condition affecting the Linux kernel version 3.13.6 and earlier. This flaw exists within the inet_frag_intern function located in net/ipv4/inet_fragment.c, which handles the processing of fragmented internet protocol packets. The race condition manifests when the system processes a large series of fragmented ICMP Echo Request packets under conditions of heavy CPU load, creating a window where concurrent operations can lead to improper memory management. The vulnerability is classified under CWE-367, which specifically addresses Time-of-Check to Time-of-Use (TOCTOU) flaws, where the state of a resource changes between the time it is checked and when it is used, leading to potential exploitation.
The technical implementation of this vulnerability exploits the timing gap between when the kernel checks for existing fragment lists and when it performs operations on those lists. When multiple fragmented packets arrive simultaneously during high CPU utilization, the kernel's fragment handling mechanism can fail to properly synchronize access to shared memory structures. This allows an attacker to manipulate the system into attempting to use memory that has already been freed, resulting in a use-after-free error condition. The race condition occurs because the kernel does not adequately protect against concurrent access to fragment cache entries during the process of creating or updating fragment lists. This behavior aligns with ATT&CK technique T1499.004, which involves network denial of service attacks through resource exhaustion or manipulation of system memory structures.
The operational impact of this vulnerability extends beyond simple denial of service, potentially enabling more severe consequences depending on the system configuration and execution environment. A successful exploitation can cause the kernel to crash, leading to system instability and complete service disruption. Under certain conditions, the use-after-free vulnerability could potentially be leveraged to execute arbitrary code with kernel privileges, though this requires additional exploitation vectors. The vulnerability is particularly dangerous in environments where systems are already under heavy load, as the probability of triggering the race condition increases significantly. Network infrastructure devices, servers handling high volumes of traffic, and systems running with limited computational resources are especially vulnerable to this attack vector. The flaw demonstrates the complexity of kernel-level synchronization issues and highlights the challenges in maintaining memory safety in high-performance network processing environments. Organizations affected by this vulnerability must implement immediate mitigations including kernel updates to versions 3.13.7 or later, where the race condition has been properly addressed through improved locking mechanisms and memory management protocols.