{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64045","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T07:54:57.029Z","datePublished":"2026-07-19T15:39:30.526Z","dateUpdated":"2026-08-05T12:38:37.111Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:38:37.111Z"},"descriptions":[{"lang":"en","value":"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->peer, caches the peer\npointer in a local, and drops the read lock. It then passes sock->peer\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->close() without taking lock_sock first.\n\novpn_socket_release() can therefore complete its kref_put -> detach ->\nsynchronize_rcu -> kfree(sock) sequence concurrently, in the window\nafter ovpn_tcp_close() drops rcu_read_lock() but before it dereferences\nsock->peer. 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->peer exactly once into the cached\npeer local, and route all subsequent uses (the hold check, the\novpn_peer_del() call, and the prot->close() invocation) through that\nlocal. sock->peer 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."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.4,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable code runs only in ovpn_tcp_close(), reached via the close() syscall path (inet_release() -> sk_prot->close) on a TCP socket attached to the ovpn driver. Remote network packets do not directly invoke this function.\nAC:L - The reproducer is a race between closing the TCP fd and concurrent peer removal (keepalive expiry or OVPN_CMD_DEL_PEER). The attacker controls both sides by timing close() against peer deletion, and can retry until the window is hit.\nPR:N - On an internet-facing OpenVPN server with kernel TCP offload, a remote VPN peer needs no Linux credentials: stopping traffic triggers kernel keepalive expiry and ovpn_socket_release(), while the local daemon concurrently closes the TCP socket as part of normal teardown.\nUI:N - Exploitation does not require any victim user action beyond normal automated VPN server operation reacting to peer timeout or disconnect.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the host kernel; it does not cross a VM, container, or IOMMU security boundary.\nC:H - This is a use-after-free: after RCU ends, ovpn_tcp_close() re-dereferences sock->peer on a freed ovpn_socket, enabling reads of attacker-influenced freed heap contents and potential information disclosure.\nI:H - The stale sock->peer pointer is passed to ovpn_peer_del(), which operates on peer structures and locks; corrupted pointers can cause arbitrary kernel memory corruption exploitable for control-flow hijacking.\nA:H - The UAF can cause kernel oops/panic during peer deletion or TCP close, and use-after-free on kmalloc objects routinely causes system crashes even when not fully weaponized."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ovpn/tcp.c"],"versions":[{"version":"11851cbd60ea1e5abbd97619d69845ead99303d6","lessThan":"e5460eb7238c19d651a9b22b2378b587033a4095","status":"affected","versionType":"git"},{"version":"11851cbd60ea1e5abbd97619d69845ead99303d6","lessThan":"d3ef441907fca7c340979e577a3db3bb634bf166","status":"affected","versionType":"git"},{"version":"11851cbd60ea1e5abbd97619d69845ead99303d6","lessThan":"775d8d7ad02aa345e1588424a6a8b9ae49fb9012","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ovpn/tcp.c"],"versions":[{"version":"6.16","status":"affected"},{"version":"0","lessThan":"6.16","status":"unaffected","versionType":"semver"},{"version":"6.18.34","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.0.11","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"6.18.34"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"7.0.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"7.1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/e5460eb7238c19d651a9b22b2378b587033a4095"},{"url":"https://git.kernel.org/stable/c/d3ef441907fca7c340979e577a3db3bb634bf166"},{"url":"https://git.kernel.org/stable/c/775d8d7ad02aa345e1588424a6a8b9ae49fb9012"}],"title":"ovpn: tcp - use cached peer pointer in ovpn_tcp_close()","x_generator":{"engine":"bippy-1.2.0"}}}}