CVE-2026-71226 in Red Hat
Summary
by MITRE • 08/05/2026
Memory Corruption via Uncanceled AIO Requests on Error: libkcapi's one-shot AIO path can return an error before all submitted IOCBs are drained, allowing later kernel writes into caller-owned output buffers.
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Analysis
by VulDB Data Team • 08/05/2026
This vulnerability resides in the kernel crypto API implementation known as libkcapi which provides userspace access to kernel cryptographic operations through asynchronous I/O mechanisms. The core issue manifests when the one-shot AIO path encounters an error condition but fails to properly cancel or drain all submitted IOCBs before returning control to the calling application. This memory corruption vulnerability stems from improper handling of asynchronous operations where the kernel does not guarantee that all pending I/O requests will be fully processed or cleaned up upon encountering an error state.
The technical flaw specifically occurs in the kernel's crypto API subsystem when multiple I/O control blocks are submitted for processing but only some are successfully completed before an error condition triggers early return. This creates a race condition where subsequent kernel operations may write data into memory buffers that were previously allocated by userspace applications and are no longer under proper kernel supervision. The vulnerability is classified as a memory corruption issue that can lead to arbitrary code execution or system instability, representing a direct violation of memory safety principles.
The operational impact of this vulnerability extends beyond simple memory corruption as it enables potential privilege escalation attacks targeting the kernel crypto subsystem. Attackers could exploit this weakness by carefully crafting malicious cryptographic operations that trigger the error path while maintaining control over the affected buffers. This creates opportunities for data leakage, system compromise, and denial of service conditions within systems heavily reliant on kernel crypto operations including those implementing secure communications protocols, encryption services, and cryptographic key management functions.
Mitigation strategies should focus on ensuring proper cleanup of all submitted I/O requests regardless of error conditions, implementing robust buffer management practices, and enforcing strict validation of asynchronous operation completion states. The fix requires modifications to the libkcapi implementation to guarantee that all pending IOCBs are properly drained or canceled before returning error codes to userspace applications. Security researchers should monitor for related vulnerabilities in similar kernel crypto implementations and consider applying patches that enforce proper resource cleanup mechanisms. This vulnerability aligns with CWE-129 and CWE-787 categories focusing on improper input validation and out-of-bounds writes respectively, while also mapping to ATT&CK techniques involving privilege escalation through kernel exploitation and system compromise via memory corruption vulnerabilities.