CVE-2026-74493
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk6th percentile - higher than 6% of all known CVEs
Summary
A use-after-free vulnerability was found in the Linux kernel's SMC network module during link group termination. The issue arises from insufficient socket protection against concurrent close, potentially leading to memory corruption.
Risk Assessment
A local attacker could exploit this vulnerability to escalate privileges or cause a system crash (kernel panic). In extreme cases, it may allow arbitrary code execution in kernel context.
Recommendation
Apply the official patch from your Linux kernel distributor immediately. Reboot the system after the update to ensure the new kernel is fully loaded.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: net/smc: fix socket use-after-free during link group termination __smc_lgr_terminate() drops conns_lock after finding a connection in lgr->conns_all, but before taking a reference on its socket. The connection is embedded in the socket, and its registration reference protects it only while the connection remains in the tree. A concurrent close can unregister the connection and drop that reference, freeing the socket before the termination worker reaches sock_hold(). The race is reachable when close overlaps link group termination. Local stress testing reproduced the use-after-free and KASAN reported: BUG: KASAN: slab-use-after-free in __smc_lgr_terminate.part.0 [smc] Write of size 4 by task kworker/3:3 Workqueue: events smc_lgr_terminate_work [smc] __smc_lgr_terminate.part.0 [smc] The socket was allocated by smc_create(), freed through slab_free_after_rcu_debug(), and was followed by: refcount_t: addition on 0; use-after-free. __smc_lgr_terminate.part.0 [smc] Take the socket reference while conns_lock still protects the tree entry. The unregister path then cannot drop the last reference until termination has finished using the socket.