Linux Kernel Vulnerability in SHDLC Timers and Context Management

CVE-2026-46267

What is CVE-2026-46267?

A vulnerability exists in the Linux kernel related to SHDLC (Synchronous HDLC) functionality, where improper management of timers and context can lead to a Use After Free (UAF) condition. The function llc_shdlc_deinit() attempts to purge SHDLC skb queues and free the llc_shdlc structure while active timers and state machines may still be operating. This situation can create a scenario where timer callbacks execute concurrently with the cleanup process, potentially causing unexpected behavior or access to freed memory. To mitigate this risk, it is essential to stop all SHDLC timers and cancel scheduled work synchronously before proceeding with the cleanup of queues and context memory.

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