CVE-2026-74432 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
rxrpc: Fix leak of released call in recvmsg(MSG_PEEK)
Fix rxrpc_recvmsg() to also drop the ref it holds on an already-released call if MSG_PEEK is in force (the function holds a ref on the call irrespective of whether MSG_PEEK is specified or not).
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability addressed in this linux kernel patch relates to a memory management issue within the rxrpc subsystem, specifically affecting the recvmsg function when processing messages with the MSG_PEEK flag. This represents a classic resource leak scenario where kernel objects fail to be properly released, leading to potential memory exhaustion and system instability. The rxrpc protocol implementation handles remote execution of rpc calls over datagram transports and requires careful management of reference counts for call objects to prevent premature deallocation while maintaining proper object lifecycle control.
The technical flaw manifests in the rxrpc_recvmsg() function's handling of reference counting when MSG_PEEK is specified. The function maintains a reference on call objects regardless of whether MSG_PEEK is used, but fails to properly release this reference when the call has already been released by other parts of the system. This creates a situation where the reference count remains elevated beyond the actual need for the object, preventing proper cleanup and leading to memory leaks that accumulate over time. The issue specifically affects the kernel's ability to track and release resources accurately, violating fundamental resource management principles.
Operationally, this vulnerability can lead to progressive memory consumption within the kernel address space, potentially causing system performance degradation or even system crashes under sustained load conditions. The leak occurs during message reception operations when peeking at data without consuming it, which is a legitimate network operation that should not result in resource accumulation. Attackers could theoretically exploit this by repeatedly performing peek operations on rxrpc connections to cause gradual memory exhaustion, though the direct impact may be limited since this affects kernel memory management rather than user-space processes.
The fix implements proper reference count management by ensuring that when MSG_PEEK is specified and a call has already been released, the function drops its reference appropriately. This aligns with established kernel development practices for managing object lifecycles and prevents the accumulation of stale references that would otherwise block resource cleanup. The solution follows standard memory management patterns used throughout the linux kernel where reference counting must account for all paths through code execution. This vulnerability demonstrates the importance of proper reference count accounting in kernel subsystems and relates to common security concerns identified in CWE-401, which addresses improper release of memory resources.
Mitigation strategies include applying the kernel patch immediately to affected systems and monitoring for unusual memory consumption patterns that might indicate resource leak issues. System administrators should prioritize updating kernel versions that contain this fix, particularly on servers hosting rxrpc services or systems with high network traffic volumes. The vulnerability does not require special exploitation techniques but represents a latent issue that can compound under sustained load conditions, making proactive patch management essential for maintaining system stability and preventing potential denial of service scenarios. Organizations should consider implementing memory monitoring tools to detect anomalous resource consumption patterns that could indicate similar issues in other kernel subsystems.