{"cve":"CVE-2023-52885","nvd":{"published":"2024-07-14T08:15:01.823","modified":"2026-08-04T10:18:47.780","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: Fix UAF in svc_tcp_listen_data_ready()\n\nAfter the listener svc_sock is freed, and before invoking svc_tcp_accept()\nfor the established child sock, there is a window that the newsock\nretaining a freed listener svc_sock in sk_user_data which cloning from\nparent. In the race window, if data is received on the newsock, we will\nobserve use-after-free report in svc_tcp_listen_data_ready().\n\nReproduce by two tasks:\n\n1. while :; do rpc.nfsd 0 ; rpc.nfsd; done\n2. while :; do echo \"\" | ncat -4 127.0.0.1 2049 ; done\n\nKASAN report:\n\n  ==================================================================\n  BUG: KASAN: slab-use-after-free in svc_tcp_listen_data_ready+0x1cf/0x1f0 [sunrpc]\n  Read of size 8 at addr ffff888139d96228 by task nc/102553\n  CPU: 7 PID: 102553 Comm: nc Not tainted 6.3.0+ #18\n  Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020\n  Call Trace:\n   <IRQ>\n   dump_stack_lvl+0x33/0x50\n   print_address_description.constprop.0+0x27/0x310\n   print_report+0x3e/0x70\n   kasan_report+0xae/0xe0\n   svc_tcp_listen_data_ready+0x1cf/0x1f0 [sunrpc]\n   tcp_data_queue+0x9f4/0x20e0\n   tcp_rcv_established+0x666/0x1f60\n   tcp_v4_do_rcv+0x51c/0x850\n   tcp_v4_rcv+0x23fc/0x2e80\n   ip_protocol_deliver_rcu+0x62/0x300\n   ip_local_deliver_finish+0x267/0x350\n   ip_local_deliver+0x18b/0x2d0\n   ip_rcv+0x2fb/0x370\n   __netif_receive_skb_one_core+0x166/0x1b0\n   process_backlog+0x24c/0x5e0\n   __napi_poll+0xa2/0x500\n   net_rx_action+0x854/0xc90\n   __do_softirq+0x1bb/0x5de\n   do_softirq+0xcb/0x100\n   </IRQ>\n   <TASK>\n   ...\n   </TASK>\n\n  Allocated by task 102371:\n   kasan_save_stack+0x1e/0x40\n   kasan_set_track+0x21/0x30\n   __kasan_kmalloc+0x7b/0x90\n   svc_setup_socket+0x52/0x4f0 [sunrpc]\n   svc_addsock+0x20d/0x400 [sunrpc]\n   __write_ports_addfd+0x209/0x390 [nfsd]\n   write_ports+0x239/0x2c0 [nfsd]\n   nfsctl_transaction_write+0xac/0x110 [nfsd]\n   vfs_write+0x1c3/0xae0\n   ksys_write+0xed/0x1c0\n   do_syscall_64+0x38/0x90\n   entry_SYSCALL_64_after_hwframe+0x72/0xdc\n\n  Freed by task 102551:\n   kasan_save_stack+0x1e/0x40\n   kasan_set_track+0x21/0x30\n   kasan_save_free_info+0x2a/0x50\n   __kasan_slab_free+0x106/0x190\n   __kmem_cache_free+0x133/0x270\n   svc_xprt_free+0x1e2/0x350 [sunrpc]\n   svc_xprt_destroy_all+0x25a/0x440 [sunrpc]\n   nfsd_put+0x125/0x240 [nfsd]\n   nfsd_svc+0x2cb/0x3c0 [nfsd]\n   write_threads+0x1ac/0x2a0 [nfsd]\n   nfsctl_transaction_write+0xac/0x110 [nfsd]\n   vfs_write+0x1c3/0xae0\n   ksys_write+0xed/0x1c0\n   do_syscall_64+0x38/0x90\n   entry_SYSCALL_64_after_hwframe+0x72/0xdc\n\nFix the UAF by simply doing nothing in svc_tcp_listen_data_ready()\nif state != TCP_LISTEN, that will avoid dereferencing svsk for all\nchild socket.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/42725e5c1b181b757ba11d804443922982334d9b","https://git.kernel.org/stable/c/7e1f989055622fd086c5dfb291fc72adf5660b6f","https://git.kernel.org/stable/c/c7b8c2d06e437639694abe76978e915cfb73f428","https://git.kernel.org/stable/c/cd5ec3ee52ce4b7e283cc11facfa420c297c8065","https://git.kernel.org/stable/c/dfc896c4a75cb8cd7cb2dfd9b469cf1e3f004254"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:52:42.518321223+00:00"},"epss":{"cve":"CVE-2023-52885","score":0.00557,"percentile":0.46495,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}