CVE-2025-21884

CVE.org · Published

Record status: Published
Identifier year (not publication year): 2025
Source publication: Mar 27, 2025
Source updated: Oct 15, 2026
Imported by cveboard: Oct 24, 2026
Source snapshot: cve_2026-10-24_midnight_baseline · Oct 24, 2026

CNA source text (English)

net: better track kernel sockets lifetime

In the Linux kernel, the following vulnerability has been resolved: net: better track kernel sockets lifetime While kernel sockets are dismantled during pernet_operations->exit(), their freeing can be delayed by any tx packets still held in qdisc or device queues, due to skb_set_owner_w() prior calls. This then trigger the following warning from ref_tracker_dir_exit() [1] To fix this, make sure that kernel sockets own a reference on net->passive. Add sk_net_refcnt_upgrade() helper, used whenever a kernel socket is converted to a refcounted one. [1] [ 136.263918][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at [ 136.263918][ T35] sk_alloc+0x2b3/0x370 [ 136.263918][ T35] inet6_create+0x6ce/0x10f0 [ 136.263918][ T35] __sock_create+0x4c0/0xa30 [ 136.263918][ T35] inet_ctl_sock_create+0xc2/0x250 [ 136.263918][ T35] igmp6_net_init+0x39/0x390 [ 136.263918][ T35] ops_init+0x31e/0x590 [ 136.263918][ T35] setup_net+0x287/0x9e0 [ 136.263918][ T35] copy_net_ns+0x33f/0x570 [ 136.263918][ T35] create_new_namespaces+0x425/0x7b0 [ 136.263918][ T35] unshare_nsproxy_namespaces+0x124/0x180 [ 136.263918][ T35] ksys_unshare+0x57d/0xa70 [ 136.263918][ T35] __x64_sys_unshare+0x38/0x40 [ 136.263918][ T35] do_syscall_64+0xf3/0x230 [ 136.263918][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 136.263918][ T35] [ 136.343488][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at [ 136.343488][ T35] sk_alloc+0x2b3/0x370 [ 136.343488][ T35] inet6_create+0x6ce/0x10f0 [ 136.343488][ T35] __sock_create+0x4c0/0xa30 [ 136.343488][ T35] inet_ctl_sock_create+0xc2/0x250 [ 136.343488][ T35] ndisc_net_init+0xa7/0x2b0 [ 136.343488][ T35] ops_init+0x31e/0x590 [ 136.343488][ T35] setup_net+0x287/0x9e0 [ 136.343488][ T35] copy_net_ns+0x33f/0x570 [ 136.343488][ T35] create_new_namespaces+0x425/0x7b0 [ 136.343488][ T35] unshare_nsproxy_namespaces+0x124/0x180 [ 136.343488][ T35] ksys_unshare+0x57d/0xa70 [ 136.343488][ T35] __x64_sys_unshare+0x38/0x40 [ 136.343488][ T35] do_syscall_64+0xf3/0x230 [ 136.343488][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f

Scoped product and version facts

Fix information unknown; no fixed version is derived here. Missing information does not prove that no fix exists.

Exploitation unknown; this catalogue does not assess exploitation.

Linux

Vendor: Linux
Product: Linux
Platforms: Unknown
Default status: unaffected

Linux · Scoped product and version facts
Version (version)	Status (status)	Version scheme (versionType)	Exclusive end (lessThan)	Inclusive end (lessThanOrEqual)	Status changes (at → status)
0cafd77dcd032d1687efaba5598cf07bce85997f	`affected`	git	2668e038800b946d269f96ec1b258c01930a242c	Unavailable	None listed
0cafd77dcd032d1687efaba5598cf07bce85997f	`affected`	git	4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb	Unavailable	None listed
0cafd77dcd032d1687efaba5598cf07bce85997f	`affected`	git	c31a732fac46b00b95b78fcc9c37cb48dd6f2e0c	Unavailable	None listed
0cafd77dcd032d1687efaba5598cf07bce85997f	`affected`	git	5c70eb5c593d64d93b178905da215a9fd288a4b5	Unavailable	None listed

Linux

Vendor: Linux
Product: Linux
Platforms: Unknown
Default status: affected

Linux · Scoped product and version facts
Version (version)	Status (status)	Version scheme (versionType)	Exclusive end (lessThan)	Inclusive end (lessThanOrEqual)	Status changes (at → status)
6.2	`affected`	Unavailable	Unavailable	Unavailable	None listed
0	`unaffected`	semver	6.2	Unavailable	None listed
6.6.103	`unaffected`	semver	Unavailable	6.6.*	None listed
6.12.43	`unaffected`	semver	Unavailable	6.12.*	None listed
6.13.6	`unaffected`	semver	Unavailable	6.13.*	None listed
6.14	`unaffected`	original_commit_for_fix	Unavailable	*	None listed