{"id":"CVE-2025-21884","title":"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 he…","summary":"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 he…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 6.2, < 6.6.103","linux_kernel >= 6.7, < 6.12.43","linux_kernel >= 6.13, < 6.13.6","linux_kernel = 6.14"],"patched":["linux_kernel 6.13.6"],"published":"2025-03-27","updated":"2026-07-30","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-21884","references":[{"url":"https://git.kernel.org/stable/c/2668e038800b946d269f96ec1b258c01930a242c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5c70eb5c593d64d93b178905da215a9fd288a4b5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c31a732fac46b00b95b78fcc9c37cb48dd6f2e0c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-21884.json"},{"url":"https://access.redhat.com/security/cve/CVE-2025-21884"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2355399"},{"url":"https://www.cve.org/CVERecord?id=CVE-2025-21884"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-21884"},{"url":"https://lore.kernel.org/linux-cve-announce/2025032713-CVE-2025-21884-b70c@gregkh/T"}],"tags":["nvd","csaf","vex","red-hat","score-dispute"],"epss":0.00213,"epssPercentile":0.11901,"ingestedAt":"2026-07-30T06:53:10.701Z","cwe":["CWE-911"],"scores":{"nvd":7.8,"vendor":3.3},"slug":"CVE-2025-21884","body":"## Overview\n\nIn 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\n\n## Affected\n\n- `linux_kernel >= 6.2, < 6.6.103`\n- `linux_kernel >= 6.7, < 6.12.43`\n- `linux_kernel >= 6.13, < 6.13.6`\n- `linux_kernel = 6.14`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.13.6`\n\n## Vendor advisories\n\n- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · updated 2026-09-13 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-21884.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}