{
  "threat_severity" : "Low",
  "public_date" : "2025-10-04T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: nfsd: clean up potential nfsd_file refcount leaks in COPY codepath",
    "id" : "2401548",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2401548"
  },
  "cvss3" : {
    "cvss3_base_score" : "5.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-911",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nnfsd: clean up potential nfsd_file refcount leaks in COPY codepath\nThere are two different flavors of the nfsd4_copy struct. One is\nembedded in the compound and is used directly in synchronous copies. The\nother is dynamically allocated, refcounted and tracked in the client\nstruture. For the embedded one, the cleanup just involves releasing any\nnfsd_files held on its behalf. For the async one, the cleanup is a bit\nmore involved, and we need to dequeue it from lists, unhash it, etc.\nThere is at least one potential refcount leak in this code now. If the\nkthread_create call fails, then both the src and dst nfsd_files in the\noriginal nfsd4_copy object are leaked.\nThe cleanup in this codepath is also sort of weird. In the async copy\ncase, we'll have up to four nfsd_file references (src and dst for both\nflavors of copy structure). They are both put at the end of\nnfsd4_do_async_copy, even though the ones held on behalf of the embedded\none outlive that structure.\nChange it so that we always clean up the nfsd_file refs held by the\nembedded copy structure before nfsd4_copy returns. Rework\ncleanup_async_copy to handle both inter and intra copies. Eliminate\nnfsd4_cleanup_intra_ssc since it now becomes a no-op.", "A reference leak flaw was found in the Linux kernel's NFS server implementation in the file copy operation handling. \nA local user can trigger this issue when asynchronous copy operations fail to create worker threads, causing nfsd_file references held by the embedded copy structure to leak. This results in permanent reference leaks preventing proper file cleanup and leading to resource exhaustion and denial of service." ],
  "statement" : "The NFSD COPY operation supports both synchronous and asynchronous modes. For synchronous copies, an nfsd4_copy structure is embedded in the compound and holds nfsd_file references for the duration of the operation. For asynchronous copies, a separate dynamically allocated structure is created with its own references. The cleanup logic is asymmetric—the async copy structure releases its references in nfsd4_do_async_copy, but this function also releases the references from the embedded structure, even though that structure outlives the async operation. Additionally, if kthread_create fails for async copies, neither set of references is properly released, creating a permanent leak. The fix ensures embedded structure references are always cleaned up before the function returns and consolidates cleanup logic.",
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2023-05-09T00:00:00Z",
    "advisory" : "RHSA-2023:2458",
    "cpe" : "cpe:/a:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-284.11.1.el9_2"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2023-05-09T00:00:00Z",
    "advisory" : "RHSA-2023:2458",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-284.11.1.el9_2"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Out of support scope",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2023-53606\nhttps://nvd.nist.gov/vuln/detail/CVE-2023-53606\nhttps://lore.kernel.org/linux-cve-announce/2025100432-CVE-2023-53606-8c1a@gregkh/T" ],
  "name" : "CVE-2023-53606",
  "csaw" : false
}