CVE-2026-74433 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
rxrpc: Fix UAF in rxgk_issue_challenge()
Fix rxgk_issue_challenge() to free the page containing the challenge content after invoking the tracepoint as the whdr passed to the tracepoint points into the page just freed.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability identified in the Linux kernel represents a use-after-free condition within the rxrpc subsystem, specifically affecting the rxgk_issue_challenge() function. This issue arises from improper memory management during the challenge generation process for remote execution protocol security operations. The flaw demonstrates a classic memory safety vulnerability where a memory page containing challenge content is freed before all references to that memory are properly handled, creating potential attack vectors for malicious actors seeking to exploit kernel memory corruption.
The technical implementation of this vulnerability stems from the sequence of operations within rxgk_issue_challenge() function where the whdr parameter points to memory within a page that gets freed immediately after being passed to a tracepoint. This creates a temporal window where the tracepoint callback may attempt to access memory that has already been deallocated, leading to undefined behavior and potential system instability. The vulnerability operates at the kernel level, making it particularly dangerous as it can be exploited to gain elevated privileges or cause denial of service conditions.
From an operational perspective, this use-after-free vulnerability exposes systems running affected Linux kernels to potential exploitation by attackers who could leverage the memory corruption to execute arbitrary code with kernel privileges. The impact extends beyond simple system crashes as the vulnerability's nature allows for more sophisticated attack vectors including privilege escalation and persistent system compromise. The vulnerability affects systems utilizing the rxrpc protocol stack, which is commonly found in distributed computing environments and network services requiring secure remote execution capabilities.
The fix implemented addresses this vulnerability by reordering the memory management sequence to ensure that tracepoint callbacks complete execution before the page containing challenge data is freed. This approach aligns with established security practices for preventing use-after-free conditions and follows the principles outlined in common weakness enumeration CWE-416, which specifically addresses use-after-free vulnerabilities. The mitigation strategy emphasizes proper resource management and temporal memory access control, ensuring that all references to allocated memory are resolved before deallocation occurs.
Security practitioners should prioritize patching affected systems as this vulnerability represents a significant risk to kernel integrity and system security. The fix demonstrates the importance of careful memory management in kernel code and highlights the need for rigorous testing of tracepoint integration with memory allocation patterns. Organizations utilizing Linux-based systems in production environments must ensure immediate deployment of the patched kernel versions to protect against potential exploitation attempts targeting this specific use-after-free condition within the rxrpc subsystem.