CriticalFix available

net/smc: fix socket use-after-free during link group termination

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: net/smc: fix socket use-after-free during link group termination __smc_lgr_terminate() drops conns_lock after finding a connection in lgr->conns_all, but before taking a reference on its socket. The connection is embedded in the socket, and its registration reference protects it only while the connection remains in the tree. A concurrent close can unregister the connection and drop that reference, freeing the socket before the termination worker reaches sock_hold(). The race is reachable when close overlaps link group termination. Local stress testing reproduced the use-after-free and KASAN reported: BUG: KASAN: slab-use-after-free in __smc_lgr_terminate.part.0 [smc] Write of size 4 by task kworker/3:3 Workqueue: events smc_lgr_terminate_work [smc] __smc_lgr_terminate.part.0 [smc] The socket was allocated by smc_create(), freed through slab_free_after_rcu_debug(), and was followed by: refcount_t: addition on 0; use-after-free. __smc_lgr_terminate.part.0 [smc] Take the socket reference while conns_lock still protects the tree entry. The unregister path then cannot drop the last reference until termination has finished using the socket.

Products: Kernel
Affected versions: Not specified
Fixed versions: 5.10.265, 5.15.216, 6.1.183, 6.12.103, 6.18.44, 6.6.151, 7.1.8
CVEs: CVE-2026-74493
Confirmed fixed CVEs: Not specified
Updated in this feed: 3 Nov 2026, 01:33 UTC · Revision 1

Source evidence

net/smc: fix socket use-after-free during link group termination

core-osv · Original source

Published 15 Aug 2026, 12:27 UTC

osv:CVE-2026-74493

Kernel

Fixed versions: 5.10.265, 5.15.216, 6.1.183, 6.6.151, 6.12.103, 6.18.44, 7.1.8

Complete source record

{
  "id": "719c9fd3c2737f0d5b8a29afab5fb9ea3c4ea68414c4d289f3c59111558338d6",
  "url": "https://osv.dev/vulnerability/CVE-2026-74493",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net/smc: fix socket use-after-free during link group termination",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: net/smc: fix socket use-after-free during link group termination __smc_lgr_terminate() drops conns_lock after finding a connection in lgr->conns_all, but before taking a reference on its socket. The connection is embedded in the socket, and its registration reference protects it only while the connection remains in the tree. A concurrent close can unregister the connection and drop that reference, freeing the socket before the termination worker reaches sock_hold(). The race is reachable when close overlaps link group termination. Local stress testing reproduced the use-after-free and KASAN reported: BUG: KASAN: slab-use-after-free in __smc_lgr_terminate.part.0 [smc] Write of size 4 by task kworker/3:3 Workqueue: events smc_lgr_terminate_work [smc] __smc_lgr_terminate.part.0 [smc] The socket was allocated by smc_create(), freed through slab_free_after_rcu_debug(), and was followed by: refcount_t: addition on 0; use-after-free. __smc_lgr_terminate.part.0 [smc] Take the socket reference while conns_lock still protects the tree entry. The unregister path then cannot drop the last reference until termination has finished using the socket.",
    "evidence": "osv:CVE-2026-74493",
    "products": [
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      "modified": "2026-10-28T02:30:25.052765462Z",
      "provider": "osv",
      "references": [
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        "https://git.kernel.org/stable/c/5a42f162b857019a4c10ff687dc3bcdf51831865",
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      "provider_metadata": {
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    "severity_evidence": "/severity/0/score"
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  "source_id": "core-osv",
  "document_id": 491672,
  "published_at": "2026-08-15T12:27:21.98+00:00"
}