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

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2026-74493

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-74493

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "69318b5215f2dc32c345a3d65b98b4b1bf29c007",
        "lessThan": "ff44f2df57fb5560bdc75eb977867643e764a262",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "69318b5215f2dc32c345a3d65b98b4b1bf29c007",
        "lessThan": "9fb17c95b8f0683570fca1fb2792264147af937a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "69318b5215f2dc32c345a3d65b98b4b1bf29c007",
        "lessThan": "bea8dc14de2d56aca749d368563e6888217710a5",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "69318b5215f2dc32c345a3d65b98b4b1bf29c007",
        "lessThan": "5a42f162b857019a4c10ff687dc3bcdf51831865",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "69318b5215f2dc32c345a3d65b98b4b1bf29c007",
        "lessThan": "281c103a8eaed59001ce952f231df1b07674215a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "69318b5215f2dc32c345a3d65b98b4b1bf29c007",
        "lessThan": "f807a63d0d95680c34f677700da9148a07d7c78f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "69318b5215f2dc32c345a3d65b98b4b1bf29c007",
        "lessThan": "f0541a775d04c88e90ba448e35ce0d743512822a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "69318b5215f2dc32c345a3d65b98b4b1bf29c007",
        "lessThan": "f621d6ebeebb6374342571e4ddf45fdbc420f6cd",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/smc/smc_core.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.5"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.5",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.265",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.216",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.183",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.151",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.103",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.44",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.8",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/smc/smc_core.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-74493

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#33178 · Revision 1
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Publisher date
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