{"cve":"CVE-2022-49979","nvd":{"published":"2025-06-18T11:15:25.363","modified":"2026-10-15T22:17:26.610","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: fix refcount bug in sk_psock_get (2)\n\nSyzkaller reports refcount bug as follows:\n------------[ cut here ]------------\nrefcount_t: saturated; leaking memory.\nWARNING: CPU: 1 PID: 3605 at lib/refcount.c:19 refcount_warn_saturate+0xf4/0x1e0 lib/refcount.c:19\nModules linked in:\nCPU: 1 PID: 3605 Comm: syz-executor208 Not tainted 5.18.0-syzkaller-03023-g7e062cda7d90 #0\n <TASK>\n __refcount_add_not_zero include/linux/refcount.h:163 [inline]\n __refcount_inc_not_zero include/linux/refcount.h:227 [inline]\n refcount_inc_not_zero include/linux/refcount.h:245 [inline]\n sk_psock_get+0x3bc/0x410 include/linux/skmsg.h:439\n tls_data_ready+0x6d/0x1b0 net/tls/tls_sw.c:2091\n tcp_data_ready+0x106/0x520 net/ipv4/tcp_input.c:4983\n tcp_data_queue+0x25f2/0x4c90 net/ipv4/tcp_input.c:5057\n tcp_rcv_state_process+0x1774/0x4e80 net/ipv4/tcp_input.c:6659\n tcp_v4_do_rcv+0x339/0x980 net/ipv4/tcp_ipv4.c:1682\n sk_backlog_rcv include/net/sock.h:1061 [inline]\n __release_sock+0x134/0x3b0 net/core/sock.c:2849\n release_sock+0x54/0x1b0 net/core/sock.c:3404\n inet_shutdown+0x1e0/0x430 net/ipv4/af_inet.c:909\n __sys_shutdown_sock net/socket.c:2331 [inline]\n __sys_shutdown_sock net/socket.c:2325 [inline]\n __sys_shutdown+0xf1/0x1b0 net/socket.c:2343\n __do_sys_shutdown net/socket.c:2351 [inline]\n __se_sys_shutdown net/socket.c:2349 [inline]\n __x64_sys_shutdown+0x50/0x70 net/socket.c:2349\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x46/0xb0\n </TASK>\n\nDuring SMC fallback process in connect syscall, kernel will\nreplaces TCP with SMC. In order to forward wakeup\nsmc socket waitqueue after fallback, kernel will sets\nclcsk->sk_user_data to origin smc socket in\nsmc_fback_replace_callbacks().\n\nLater, in shutdown syscall, kernel will calls\nsk_psock_get(), which treats the clcsk->sk_user_data\nas psock type, triggering the refcnt warning.\n\nSo, the root cause is that smc and psock, both will use\nsk_user_data field. So they will mismatch this field\neasily.\n\nThis patch solves it by using another bit(defined as\nSK_USER_DATA_PSOCK) in PTRMASK, to mark whether\nsk_user_data points to a psock object or not.\nThis patch depends on a PTRMASK introduced in commit f1ff5ce2cd5e\n(\"net, sk_msg: Clear sk_user_data pointer on clone if tagged\").\n\nFor there will possibly be more flags in the sk_user_data field,\nthis patch also refactor sk_user_data flags code to be more generic\nto improve its maintainability.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/2a0133723f9ebeb751cfce19f74ec07e108bef1f","https://git.kernel.org/stable/c/86026be8535c16fcc5e4f960286faf04d7f77815","https://git.kernel.org/stable/c/a5d1cb908131e939bd8b63b8e5e23365bbc2edaf"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:03:23.287444849+00:00"},"epss":{"cve":"CVE-2022-49979","score":0.00265,"percentile":0.18266,"date":"2026-10-25"},"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."]}