{"id":"CVE-2026-64045","summary":"ovpn: tcp - use cached peer pointer in ovpn_tcp_close()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\novpn: tcp - use cached peer pointer in ovpn_tcp_close()\n\novpn_tcp_close() loads the ovpn_socket via rcu_dereference_sk_user_data()\nunder rcu_read_lock(), takes a reference on sock-\u003epeer, caches the peer\npointer in a local, and drops the read lock. It then passes sock-\u003epeer\n(rather than the cached local) to ovpn_peer_del(), re-dereferencing the\novpn_socket after the RCU read section has ended.\n\nUnlike ovpn_tcp_sendmsg(), which uses the same \"load under RCU, use\nafter unlock\" pattern but is protected by lock_sock() held across the\nfunction, ovpn_tcp_close() runs without the socket lock: inet_release()\ninvokes sk_prot-\u003eclose() without taking lock_sock first.\n\novpn_socket_release() can therefore complete its kref_put -\u003e detach -\u003e\nsynchronize_rcu -\u003e kfree(sock) sequence concurrently, in the window\nafter ovpn_tcp_close() drops rcu_read_lock() but before it dereferences\nsock-\u003epeer. The synchronize_rcu() in ovpn_socket_release() protects\nreaders that use the dereferenced pointer inside the RCU read section,\nnot those that escape the pointer to a local and use it afterwards.\n\nA reproducer follows the pattern of commit 94560267d6c4 (\"ovpn: tcp -\ndon't deref NULL sk_socket member after tcp_close()\"): trigger a peer\nremoval (keepalive expiration or netlink OVPN_CMD_DEL_PEER) at the same\nmoment userspace closes the TCP fd. That commit fixed the detach-side\nof the same race window; this one fixes the close-side at a different\nvictim.\n\nTighten the entry block to read sock-\u003epeer exactly once into the cached\npeer local, and route all subsequent uses (the hold check, the\novpn_peer_del() call, and the prot-\u003eclose() invocation) through that\nlocal. sock-\u003epeer is only ever written once in ovpn_socket_new() under\nlock_sock(), before rcu_assign_sk_user_data() publishes the ovpn_socket,\nand is never reassigned afterwards - but the previous multi-read pattern\nmade that invariant implicit rather than explicit. The same multi-read\nshape exists in ovpn_tcp_recvmsg(), ovpn_tcp_sendmsg(),\novpn_tcp_data_ready() and ovpn_tcp_write_space(); those will be cleaned\nup via a dedicated helper in a follow-up net-next series.","modified":"2026-07-22T05:30:00.214064043Z","published":"2026-07-19T15:39:30.526Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64045.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/775d8d7ad02aa345e1588424a6a8b9ae49fb9012"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d3ef441907fca7c340979e577a3db3bb634bf166"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e5460eb7238c19d651a9b22b2378b587033a4095"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64045.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64045"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"11851cbd60ea1e5abbd97619d69845ead99303d6"},{"fixed":"e5460eb7238c19d651a9b22b2378b587033a4095"},{"fixed":"d3ef441907fca7c340979e577a3db3bb634bf166"},{"fixed":"775d8d7ad02aa345e1588424a6a8b9ae49fb9012"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64045.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.16.0"},{"fixed":"6.18.34"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64045.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}