Memory Management Flaw in Linux Kernel Affecting Pipe Functionality

CVE-2026-99203

What is CVE-2026-99203?

A vulnerability in the Linux kernel's handling of pipes may lead to improper management of asynchronous readers during writer setup failures. This issue arises when the F_SETFL and FIOASYNC flags are set. The fasync_helper function doesn't check existing entries before allocation, which can lead to a condition where a second enable for an O_RDWR FIFO can overwrite the reader entry while failing to allocate for the writer. Consequently, the error handling might leave the reader registered while failing to deregister during the writer's failure. An attacker could reproduce this vulnerabilities using memory pressure, leading to possible exploitation through slab-use-after-free scenarios in the send_sigio function.

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