CVE-2018-5332 in Linux
Summary
by MITRE
In the Linux kernel through 4.14.13, the rds_message_alloc_sgs() function does not validate a value that is used during DMA page allocation, leading to a heap-based out-of-bounds write (related to the rds_rdma_extra_size function in net/rds/rdma.c).
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Analysis
by VulDB Data Team • 09/14/2025
The vulnerability identified as CVE-2018-5332 represents a critical heap-based out-of-bounds write flaw within the Linux kernel version 4.14.13 and earlier. This issue resides in the rds_message_alloc_sgs() function which forms part of the Reliable Datagram Sockets (RDS) subsystem designed for high-performance inter-node communication in Linux environments. The vulnerability stems from inadequate validation of a parameter that controls DMA page allocation operations, creating a scenario where malicious input can trigger memory corruption beyond intended boundaries.
The technical flaw manifests when the rds_rdma_extra_size function processes data that eventually flows into the rds_message_alloc_sgs() function. This function fails to properly validate the size parameter used during memory allocation for scatter-gather lists, which are essential data structures for managing I/O operations in network drivers. When an attacker crafts malicious RDS packets with specially crafted payload sizes, the function accepts invalid values that cause the kernel to allocate memory chunks that are insufficient for the intended operation, resulting in writes that extend beyond allocated heap memory regions.
This vulnerability operates at the kernel level and presents significant operational impact for systems utilizing the RDS protocol for inter-process communication. The heap-based out-of-bounds write creates opportunities for arbitrary code execution, memory corruption, and potential privilege escalation within the kernel space. Systems running affected kernel versions are particularly vulnerable when processing untrusted RDS traffic, making this flaw especially dangerous in networked environments where external attackers could exploit it to gain unauthorized access or disrupt system operations. The vulnerability is classified under CWE-121 as a heap-based buffer overflow, which directly relates to improper validation of memory allocation parameters.
The operational implications extend beyond immediate exploitation as this flaw can lead to system instability, denial of service conditions, and potential data corruption across kernel memory regions. Attackers leveraging this vulnerability could manipulate kernel memory structures, potentially compromising the integrity of the entire system. The attack surface includes any system that enables RDS functionality or processes RDS traffic, making it particularly concerning for high-performance computing clusters, database servers, and network infrastructure devices. Mitigation strategies should focus on kernel updates to versions beyond 4.14.13, along with implementing network segmentation and monitoring for suspicious RDS traffic patterns. This vulnerability aligns with ATT&CK technique T1068 for local privilege escalation and T1499 for network denial of service attacks, demonstrating its multi-faceted threat potential within cybersecurity frameworks.