CVE-2022-1012 in Linux
Summary
by MITRE • 08/05/2022
A memory leak problem was found in the TCP source port generation algorithm in net/ipv4/tcp.c due to the small table perturb size. This flaw may allow an attacker to information leak and may cause a denial of service problem.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 04/03/2026
The vulnerability identified as CVE-2022-1012 represents a critical memory management issue within the Linux kernel's TCP implementation that manifests through the source port generation algorithm. This flaw resides in the net/ipv4/tcp.c source file where the kernel's handling of TCP source port allocation demonstrates inadequate memory table management. The core problem stems from a limited perturb size within the hash table structure used for source port selection, creating conditions where memory resources become progressively consumed during network connection establishment processes. The vulnerability operates at the kernel level within the networking stack, specifically targeting the TCP protocol implementation that governs how source ports are allocated for outgoing connections. This memory leak occurs during the normal operation of TCP connections when the kernel attempts to maintain a hash table of previously used source ports to prevent conflicts and ensure proper port allocation.
The technical mechanism behind this vulnerability involves the perturb value used in hash table calculations for source port selection. When the perturb size remains small, the hash table experiences increased collision rates during port allocation operations. Each time a new TCP connection is established, the kernel attempts to find an available source port while maintaining the hash table structure. As the table fills with entries and collisions increase due to the limited perturb size, the system gradually consumes additional memory resources without proper cleanup. This memory consumption grows progressively with each connection attempt, eventually leading to memory exhaustion in the kernel's networking subsystem. The flaw demonstrates characteristics of a resource exhaustion vulnerability where the memory leak accumulates over time, making it particularly dangerous in high-traffic network environments. The vulnerability affects all Linux kernel versions that implement the problematic TCP source port generation algorithm, with the issue being classified under CWE-401 as a failure to release memory resources.
The operational impact of CVE-2022-1012 extends beyond simple memory consumption to potentially compromise system availability and stability. When the memory leak reaches critical levels, the kernel's networking subsystem may become unresponsive or crash entirely, resulting in denial of service conditions that affect all network services running on the affected system. Network administrators may observe gradual performance degradation, system instability, and eventual complete service interruption as the memory leak progresses. The vulnerability can be exploited by remote attackers who continuously establish TCP connections to the target system, causing rapid memory consumption and system exhaustion. This attack vector aligns with ATT&CK technique T1499.004 which involves resource exhaustion attacks targeting system availability. The impact is particularly severe in server environments where high connection volumes are normal, as the memory leak can compound quickly under sustained attack conditions, potentially leading to complete system failure and requiring manual intervention for recovery.
Mitigation strategies for CVE-2022-1012 require both immediate patching and operational monitoring to address the root cause of the memory leak. The primary solution involves applying the official kernel patches that increase the perturb table size and improve memory management within the TCP source port generation algorithm. Organizations should prioritize updating their kernel versions to patched releases that contain the corrected implementation of the hash table management for source port allocation. System administrators should implement monitoring solutions to track memory usage patterns and network connection rates to detect early signs of the memory leak occurring. Additionally, implementing connection rate limiting and connection tracking mechanisms can help mitigate the impact of potential exploitation attempts by limiting the rate at which new connections can be established. The vulnerability demonstrates the importance of proper memory management in kernel space operations and highlights the need for thorough testing of networking components under stress conditions. Network security teams should also consider implementing intrusion detection systems that can identify unusual connection patterns that may indicate exploitation attempts targeting this specific memory leak vulnerability.