CVE-2026-23239: Concurrent Execution using Shared Resource with Improper Synchronization

In the Linux kernel, the following vulnerability has been resolved:

espintcp: Fix race condition in espintcp_close()

This issue was discovered during a code audit.

After cancel_work_sync() is called from espintcp_close(), espintcp_tx_work() can still be scheduled from paths such as the Delayed ACK handler or ksoftirqd. As a result, the espintcp_tx_work() worker may dereference a freed espintcp ctx or sk.

The following is a simple race scenario:

cpu0 cpu1

espintcp_close() cancel_work_sync(&ctx->work); espintcp_write_space() schedule_work(&ctx->work);

To prevent this race condition, cancel_work_sync() is replaced with disable_work_sync().