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nbd: don't allow reconnect after disconnect

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: nbd: don't allow reconnect after disconnect Following process can cause nbd_config UAF: 1) grab nbd_config temporarily; 2) nbd_genl_disconnect() flush all recv_work() and release the initial reference: nbd_genl_disconnect nbd_disconnect_and_put nbd_disconnect flush_workqueue(nbd->recv_workq) if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, ...)) nbd_config_put -> due to step 1), reference is still not zero 3) nbd_genl_reconfigure() queue recv_work() again; nbd_genl_reconfigure config = nbd_get_config_unlocked(nbd) if (!config) -> succeed if (!test_bit(NBD_RT_BOUND, ...)) -> succeed nbd_reconnect_socket queue_work(nbd->recv_workq, &args->work) 4) step 1) release the reference; 5) Finially, recv_work() will trigger UAF: recv_work nbd_config_put(nbd) -> nbd_config is freed atomic_dec(&config->recv_threads) -> UAF Fix the problem by clearing NBD_RT_BOUND in nbd_genl_disconnect(), so that nbd_genl_reconfigure() will fail.

Announced Source revision 1
Original source ↗

CVE-2025-21731

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-2025-21731

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": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
        "lessThan": "e70a578487a47d7cf058904141e586684d1c3381",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
        "lessThan": "6bef6222a3f6c7adb6396f77f25a3579d821b09a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
        "lessThan": "e3be8862d73cac833e0fb7602636c19c6cb94b11",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
        "lessThan": "e7343fa33751cb07c1c56b666bf37cfca357130e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
        "lessThan": "d208d2c52b652913b5eefc8ca434b0d6b757f68f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
        "lessThan": "a8ee6ecde2b7bfb58c8a3afe8a9d2b848f580739",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
        "lessThan": "9793bd5ae4bdbdb2dde401a3cab94a6bfd05e302",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
        "lessThan": "844b8cdc681612ff24df62cdefddeab5772fadf1",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "drivers/block/nbd.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.12"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.12",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.4.291",
        "versionType": "semver",
        "lessThanOrEqual": "5.4.*"
      },
      {
        "status": "unaffected",
        "version": "5.10.235",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.179",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.129",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.76",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.13",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.13.2",
        "versionType": "semver",
        "lessThanOrEqual": "6.13.*"
      },
      {
        "status": "unaffected",
        "version": "6.14",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "drivers/block/nbd.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2025-21731

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#26926 · Revision 1
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Publisher date
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