CVE-2026-74505 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
ALSA: 6fire: Fix UAF at error handling during probe
Although 6fire driver had a few fixes for dealing with the early error handling during the probe phase, it forgot a pending URB before freeing the resources, which may lead to a UAF.
This patch addresses it by doing the almost same cleanup procedure like the normal disconnect phase at the error path.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability identified in the Linux kernel's ALSA 6fire driver represents a critical use-after-free condition that emerges during the device probe phase. This flaw occurs when the driver encounters an error while initializing hardware components, specifically within the early stages of device detection and resource allocation. The 6fire driver, designed to support certain FireWire audio devices, implements complex initialization procedures that involve managing asynchronous transfer requests through the USB Request Block (URB) mechanism. During normal operation, the driver properly handles URB cleanup during disconnect events, but fails to perform identical cleanup operations when errors occur during the probe phase.
The technical implementation of this vulnerability stems from improper resource management within the error handling pathway of the driver's probe function. When hardware initialization encounters a failure, the code path attempts to free allocated resources without first canceling or waiting for pending URBs to complete their execution. This creates a scenario where memory locations that were previously allocated to URB structures become accessible for reuse while still being referenced by asynchronous operations, leading to unpredictable behavior and potential privilege escalation capabilities. The flaw directly maps to CWE-416, which describes use-after-free conditions in software systems, particularly those involving asynchronous operations and resource cleanup sequences.
The operational impact of this vulnerability extends beyond simple system instability, potentially enabling malicious actors to execute arbitrary code with kernel-level privileges. Attackers could exploit this condition by triggering a specific sequence that causes the driver to enter error handling mode during probe operations while URBs remain pending. The timing and memory state created by this race condition allows for memory corruption that could be leveraged to gain unauthorized access to system resources, manipulate kernel data structures, or escalate privileges from unprivileged user contexts to root-level access. This vulnerability particularly affects systems running Linux kernels with the affected ALSA 6fire driver implementation and represents a significant security risk in environments where audio device enumeration occurs dynamically.
The fix implemented addresses this issue by standardizing the cleanup procedure across all execution paths within the driver's probe function. The patch ensures that when errors occur during device initialization, the driver follows the same resource cleanup sequence used during normal disconnect operations, including proper URB cancellation and completion waiting before memory deallocation. This approach eliminates the race condition that previously allowed pending URBs to reference freed memory locations, thereby preventing the use-after-free scenario. The mitigation strategy aligns with established security practices for asynchronous programming patterns and follows ATT&CK framework techniques related to privilege escalation through kernel exploitation, specifically targeting the T1068 technique of exploiting vulnerabilities in system libraries and drivers. This remediation approach ensures that all code paths maintain consistent resource management protocols regardless of execution outcome, fundamentally addressing the root cause of the vulnerability through defensive programming practices and proper error handling implementation.