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CVE-2023-53781
HIGH · CVSS 7.8
EPSS exploitation probability: 0%
Published 2025-12-09T01:16:49.280 · Last modified 2026-08-04T10:19:21.043

Summary

In the Linux kernel, the following vulnerability has been resolved: smc: Fix use-after-free in tcp_write_timer_handler(). With Eric's ref tracker, syzbot finally found a repro for use-after-free in tcp_write_timer_handler() by kernel TCP sockets. [0] If SMC creates a kernel socket in __smc_create(), the kernel socket is supposed to be freed in smc_clcsock_release() by calling sock_release() when we close() the parent SMC socket. However, at the end of smc_clcsock_release(), the kernel socket's sk_state might not be TCP_CLOSE. This means that we have not called inet_csk_destroy_sock() in __tcp_close() and have not stopped the TCP timers. The kernel socket's TCP timers can be fired later, so we need to hold a refcnt for net as we do for MPTCP subflows in mptcp_subflow_create_socket().

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.