{"id":"CVE-2025-21884","revision":"ad61a128579844d6941c091b4e4f9ed3","records":[{"revision":"ad61a128579844d6941c091b4e4f9ed3","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2025-21884","aliases":[],"title":"net: better track kernel sockets lifetime","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: better track kernel sockets lifetime\n\nWhile kernel sockets are dismantled during pernet_operations->exit(),\ntheir freeing can be delayed by any tx packets still held in qdisc\nor device queues, due to skb_set_owner_w() prior calls.\n\nThis then trigger the following warning from ref_tracker_dir_exit() [1]\n\nTo fix this, make sure that kernel sockets own a reference on net->passive.\n\nAdd sk_net_refcnt_upgrade() helper, used whenever a kernel socket\nis converted to a refcounted one.\n\n[1]\n\n[ 136.263918][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at\n[ 136.263918][ T35] sk_alloc+0x2b3/0x370\n[ 136.263918][ T35] inet6_create+0x6ce/0x10f0\n[ 136.263918][ T35] __sock_create+0x4c0/0xa30\n[ 136.263918][ T35] inet_ctl_sock_create+0xc2/0x250\n[ 136.263918][ T35] igmp6_net_init+0x39/0x390\n[ 136.263918][ T35] ops_init+0x31e/0x590\n[ 136.263918][ T35] setup_net+0x287/0x9e0\n[ 136.263918][ T35] copy_net_ns+0x33f/0x570\n[ 136.263918][ T35] create_new_namespaces+0x425/0x7b0\n[ 136.263918][ T35] unshare_nsproxy_namespaces+0x124/0x180\n[ 136.263918][ T35] ksys_unshare+0x57d/0xa70\n[ 136.263918][ T35] __x64_sys_unshare+0x38/0x40\n[ 136.263918][ T35] do_syscall_64+0xf3/0x230\n[ 136.263918][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f\n[ 136.263918][ T35]\n[ 136.343488][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at\n[ 136.343488][ T35] sk_alloc+0x2b3/0x370\n[ 136.343488][ T35] inet6_create+0x6ce/0x10f0\n[ 136.343488][ T35] __sock_create+0x4c0/0xa30\n[ 136.343488][ T35] inet_ctl_sock_create+0xc2/0x250\n[ 136.343488][ T35] ndisc_net_init+0xa7/0x2b0\n[ 136.343488][ T35] ops_init+0x31e/0x590\n[ 136.343488][ T35] setup_net+0x287/0x9e0\n[ 136.343488][ T35] copy_net_ns+0x33f/0x570\n[ 136.343488][ T35] create_new_namespaces+0x425/0x7b0\n[ 136.343488][ T35] unshare_nsproxy_namespaces+0x124/0x180\n[ 136.343488][ T35] ksys_unshare+0x57d/0xa70\n[ 136.343488][ T35] __x64_sys_unshare+0x38/0x40\n[ 136.343488][ T35] do_syscall_64+0xf3/0x230\n[ 136.343488][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f","state":0,"publishedAt":"2025-03-27T14:57:12.486+00:00","modifiedAt":"2026-10-15T21:51:54.699+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"include/net/sock.h\",\n \"net/core/sock.c\",\n \"net/mptcp/subflow.c\",\n \"net/netlink/af_netlink.c\",\n \"net/rds/tcp.c\",\n \"net/smc/af_smc.c\",\n \"net/sunrpc/svcsock.c\",\n \"net/sunrpc/xprtsock.c\"\n ],\n \"versions\": [\n {\n \"version\": \"0cafd77dcd032d1687efaba5598cf07bce85997f\",\n \"lessThan\": \"2668e038800b946d269f96ec1b258c01930a242c\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0cafd77dcd032d1687efaba5598cf07bce85997f\",\n \"lessThan\": \"4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0cafd77dcd032d1687efaba5598cf07bce85997f\",\n \"lessThan\": \"c31a732fac46b00b95b78fcc9c37cb48dd6f2e0c\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0cafd77dcd032d1687efaba5598cf07bce85997f\",\n \"lessThan\": \"5c70eb5c593d64d93b178905da215a9fd288a4b5\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"include/net/sock.h\",\n \"net/core/sock.c\",\n \"net/mptcp/subflow.c\",\n \"net/netlink/af_netlink.c\",\n \"net/rds/tcp.c\",\n \"net/smc/af_smc.c\",\n \"net/sunrpc/svcsock.c\",\n \"net/sunrpc/xprtsock.c\"\n ],\n \"versions\": [\n {\n \"version\": \"6.2\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"6.2\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.103\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.43\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.13.6\",\n \"lessThanOrEqual\": \"6.13.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.14\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 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,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/2668e038800b946d269f96ec1b258c01930a242c","https://git.kernel.org/stable/c/4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb","https://git.kernel.org/stable/c/c31a732fac46b00b95b78fcc9c37cb48dd6f2e0c","https://git.kernel.org/stable/c/5c70eb5c593d64d93b178905da215a9fd288a4b5"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-21884","license":"CVE Program Terms of Use","key":"cve-program:CVE-2025-21884","identifiers":["CVE-2025-21884"]},"retained":false,"historicalAffected":[]}],"coverage":[]}