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smb: client: fix use-after-free of iface in cifs_try_adding_channels()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix use-after-free of iface in cifs_try_adding_channels() cifs_try_adding_channels() iterates ses->iface_list with list_for_each_entry_safe_from(), which captures the next entry (niface) under iface_lock. The loop body then drops iface_lock for the whole duration of cifs_ses_add_channel(). A concurrent interface refresh (SMB3_request_interfaces() -> parse_server_interfaces()) marks all ifaces inactive and removes and frees any that are not re-advertised via list_del() + kref_put(), where release_iface() is a bare kfree(). Since niface typically has no channel holding a reference, the list reference is its last and it can be freed inside the unlocked window. On continue, the iterator advance step then dereferences niface->iface_head.next, and the loop body reads iface->rdma_capable/is_active, both on freed memory. Fix this by never keeping an unreferenced list pointer across the unlocked window. Each channel attempt now re-scans the list from the head under iface_lock, takes a kref on the selected candidate, and passes only that referenced candidate to cifs_ses_add_channel(). weight_fulfilled still tracks selection progress, so restarting the scan preserves the original weighted distribution and the weight_fulfilled-before-kref_put ordering on the failure path. Add a per-pass attempts cap so a flapping interface refresh cannot keep the inner loop spinning within a single tries increment.

Announced Source revision 1
Original source ↗

CVE-2026-98173

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-2026-98173

Linux

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

Affected versions
Not stated in this record
Fixed versions
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Prerequisites
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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": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec",
        "lessThan": "ee0d8f83d68f6e6509f092c997ccab3c8c801538",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec",
        "lessThan": "c941f1ebfd26f683de81091473f3596a218abff0",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec",
        "lessThan": "e99040e5e9c60441e6b4725e1a7b88c3106ae903",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec",
        "lessThan": "ec36b38e65596950e6c29bed7dfc90b98707c19c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec",
        "lessThan": "d034e836eefd7ce75e588f7031cffbeec594f5ac",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/smb/client/sess.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.19"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.19",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.112",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.54",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.8",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/smb/client/sess.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98173

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#48868 · Revision 1
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Publisher date
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