CVE-2023-54276 (GCVE-0-2023-54276)

Vulnerability from cvelistv5 – Published: 2025-12-30 12:16 – Updated: 2026-05-11 19:58
VLAI
Title
nfsd: move init of percpu reply_cache_stats counters back to nfsd_init_net
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: move init of percpu reply_cache_stats counters back to nfsd_init_net Commit f5f9d4a314da ("nfsd: move reply cache initialization into nfsd startup") moved the initialization of the reply cache into nfsd startup, but didn't account for the stats counters, which can be accessed before nfsd is ever started. The result can be a NULL pointer dereference when someone accesses /proc/fs/nfsd/reply_cache_stats while nfsd is still shut down. This is a regression and a user-triggerable oops in the right situation: - non-x86_64 arch - /proc/fs/nfsd is mounted in the namespace - nfsd is not started in the namespace - unprivileged user calls "cat /proc/fs/nfsd/reply_cache_stats" Although this is easy to trigger on some arches (like aarch64), on x86_64, calling this_cpu_ptr(NULL) evidently returns a pointer to the fixed_percpu_data. That struct looks just enough like a newly initialized percpu var to allow nfsd_reply_cache_stats_show to access it without Oopsing. Move the initialization of the per-net+per-cpu reply-cache counters back into nfsd_init_net, while leaving the rest of the reply cache allocations to be done at nfsd startup time. Kudos to Eirik who did most of the legwork to track this down.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6638 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 4e18b58b106e34ac69d3052dd91f520bd83cf2fc , < 3025d489f9c8984d1bf5916c4a20097ed80fca5c (git)
Affected: 70fdee548c036c6bdb496f284c9e78f1654b6dd0 , < 8549384d0f65981761fe2077d04fa2a8d37b54e0 (git)
Affected: e7e571ed4ec7bb50136233d8e7b986efef2af8c1 , < 66a178177b2b3bb1d71e854c5e7bbb320eb0e566 (git)
Affected: f5f9d4a314da88c0a5faa6d168bf69081b7a25ae , < 768c408594b52d8531e1a8ab62e5620c19213e73 (git)
Affected: f5f9d4a314da88c0a5faa6d168bf69081b7a25ae , < ed9ab7346e908496816cffdecd46932035f66e2e (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.3
Unaffected: 0 , < 6.3 (semver)
Unaffected: 6.4.4 , ≤ 6.4.* (semver)
Unaffected: 6.5 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/cache.h",
            "fs/nfsd/nfscache.c",
            "fs/nfsd/nfsctl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3025d489f9c8984d1bf5916c4a20097ed80fca5c",
              "status": "affected",
              "version": "4e18b58b106e34ac69d3052dd91f520bd83cf2fc",
              "versionType": "git"
            },
            {
              "lessThan": "8549384d0f65981761fe2077d04fa2a8d37b54e0",
              "status": "affected",
              "version": "70fdee548c036c6bdb496f284c9e78f1654b6dd0",
              "versionType": "git"
            },
            {
              "lessThan": "66a178177b2b3bb1d71e854c5e7bbb320eb0e566",
              "status": "affected",
              "version": "e7e571ed4ec7bb50136233d8e7b986efef2af8c1",
              "versionType": "git"
            },
            {
              "lessThan": "768c408594b52d8531e1a8ab62e5620c19213e73",
              "status": "affected",
              "version": "f5f9d4a314da88c0a5faa6d168bf69081b7a25ae",
              "versionType": "git"
            },
            {
              "lessThan": "ed9ab7346e908496816cffdecd46932035f66e2e",
              "status": "affected",
              "version": "f5f9d4a314da88c0a5faa6d168bf69081b7a25ae",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/cache.h",
            "fs/nfsd/nfscache.c",
            "fs/nfsd/nfsctl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.3"
            },
            {
              "lessThan": "6.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.4.*",
              "status": "unaffected",
              "version": "6.4.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.5",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.4.4",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.5",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: move init of percpu reply_cache_stats counters back to nfsd_init_net\n\nCommit f5f9d4a314da (\"nfsd: move reply cache initialization into nfsd\nstartup\") moved the initialization of the reply cache into nfsd startup,\nbut didn\u0027t account for the stats counters, which can be accessed before\nnfsd is ever started. The result can be a NULL pointer dereference when\nsomeone accesses /proc/fs/nfsd/reply_cache_stats while nfsd is still\nshut down.\n\nThis is a regression and a user-triggerable oops in the right situation:\n\n- non-x86_64 arch\n- /proc/fs/nfsd is mounted in the namespace\n- nfsd is not started in the namespace\n- unprivileged user calls \"cat /proc/fs/nfsd/reply_cache_stats\"\n\nAlthough this is easy to trigger on some arches (like aarch64), on\nx86_64, calling this_cpu_ptr(NULL) evidently returns a pointer to the\nfixed_percpu_data. That struct looks just enough like a newly\ninitialized percpu var to allow nfsd_reply_cache_stats_show to access\nit without Oopsing.\n\nMove the initialization of the per-net+per-cpu reply-cache counters\nback into nfsd_init_net, while leaving the rest of the reply cache\nallocations to be done at nfsd startup time.\n\nKudos to Eirik who did most of the legwork to track this down."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T19:58:50.629Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3025d489f9c8984d1bf5916c4a20097ed80fca5c"
        },
        {
          "url": "https://git.kernel.org/stable/c/8549384d0f65981761fe2077d04fa2a8d37b54e0"
        },
        {
          "url": "https://git.kernel.org/stable/c/66a178177b2b3bb1d71e854c5e7bbb320eb0e566"
        },
        {
          "url": "https://git.kernel.org/stable/c/768c408594b52d8531e1a8ab62e5620c19213e73"
        },
        {
          "url": "https://git.kernel.org/stable/c/ed9ab7346e908496816cffdecd46932035f66e2e"
        }
      ],
      "title": "nfsd: move init of percpu reply_cache_stats counters back to nfsd_init_net",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-54276",
    "datePublished": "2025-12-30T12:16:05.020Z",
    "dateReserved": "2025-12-30T12:06:44.523Z",
    "dateUpdated": "2026-05-11T19:58:50.629Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2023-54276",
      "date": "2026-11-15",
      "epss": "0.00199",
      "percentile": "0.09835"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "fs/nfsd/cache.h",
                  "fs/nfsd/nfscache.c",
                  "fs/nfsd/nfsctl.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "3025d489f9c8984d1bf5916c4a20097ed80fca5c",
                    "status": "affected",
                    "version": "4e18b58b106e34ac69d3052dd91f520bd83cf2fc",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "8549384d0f65981761fe2077d04fa2a8d37b54e0",
                    "status": "affected",
                    "version": "70fdee548c036c6bdb496f284c9e78f1654b6dd0",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "66a178177b2b3bb1d71e854c5e7bbb320eb0e566",
                    "status": "affected",
                    "version": "e7e571ed4ec7bb50136233d8e7b986efef2af8c1",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "768c408594b52d8531e1a8ab62e5620c19213e73",
                    "status": "affected",
                    "version": "f5f9d4a314da88c0a5faa6d168bf69081b7a25ae",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "ed9ab7346e908496816cffdecd46932035f66e2e",
                    "status": "affected",
                    "version": "f5f9d4a314da88c0a5faa6d168bf69081b7a25ae",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "fs/nfsd/cache.h",
                  "fs/nfsd/nfscache.c",
                  "fs/nfsd/nfsctl.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "6.3"
                  },
                  {
                    "lessThan": "6.3",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.4.*",
                    "status": "unaffected",
                    "version": "6.4.4",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "6.5",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: move init of percpu reply_cache_stats counters back to nfsd_init_net\n\nCommit f5f9d4a314da (\"nfsd: move reply cache initialization into nfsd\nstartup\") moved the initialization of the reply cache into nfsd startup,\nbut didn\u0027t account for the stats counters, which can be accessed before\nnfsd is ever started. The result can be a NULL pointer dereference when\nsomeone accesses /proc/fs/nfsd/reply_cache_stats while nfsd is still\nshut down.\n\nThis is a regression and a user-triggerable oops in the right situation:\n\n- non-x86_64 arch\n- /proc/fs/nfsd is mounted in the namespace\n- nfsd is not started in the namespace\n- unprivileged user calls \"cat /proc/fs/nfsd/reply_cache_stats\"\n\nAlthough this is easy to trigger on some arches (like aarch64), on\nx86_64, calling this_cpu_ptr(NULL) evidently returns a pointer to the\nfixed_percpu_data. That struct looks just enough like a newly\ninitialized percpu var to allow nfsd_reply_cache_stats_show to access\nit without Oopsing.\n\nMove the initialization of the per-net+per-cpu reply-cache counters\nback into nfsd_init_net, while leaving the rest of the reply cache\nallocations to be done at nfsd startup time.\n\nKudos to Eirik who did most of the legwork to track this down."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnfsd: mover la inicializaci\u00f3n de los contadores percpu reply_cache_stats de vuelta a nfsd_init_net\n\nEl commit f5f9d4a314da (\u0027nfsd: mover la inicializaci\u00f3n de la cach\u00e9 de respuestas al inicio de nfsd\u0027) movi\u00f3 la inicializaci\u00f3n de la cach\u00e9 de respuestas al inicio de nfsd, pero no tuvo en cuenta los contadores de estad\u00edsticas, los cuales pueden ser accedidos antes de que nfsd se inicie. El resultado puede ser una desreferencia de puntero NULL cuando alguien accede a /proc/fs/nfsd/reply_cache_stats mientras nfsd a\u00fan est\u00e1 apagado.\n\nEsto es una regresi\u00f3n y un oops activable por el usuario en la situaci\u00f3n correcta:\n\n- arquitectura que no sea x86_64\n- /proc/fs/nfsd est\u00e1 montado en el espacio de nombres\n- nfsd no est\u00e1 iniciado en el espacio de nombres\n- usuario sin privilegios llama a \u0027cat /proc/fs/nfsd/reply_cache_stats\u0027\n\nAunque esto es f\u00e1cil de activar en algunas arquitecturas (como aarch64), en x86_64, llamar a this_cpu_ptr(NULL) evidentemente devuelve un puntero a los fixed_percpu_data. Esa estructura se parece lo suficiente a una variable percpu reci\u00e9n inicializada para permitir que nfsd_reply_cache_stats_show acceda a ella sin causar un Oops.\n\nMover la inicializaci\u00f3n de los contadores de cach\u00e9 de respuestas por-red+por-cpu de vuelta a nfsd_init_net, mientras se deja el resto de las asignaciones de la cach\u00e9 de respuestas para ser realizadas en el momento de inicio de nfsd.\n\nFelicitaciones a Eirik quien hizo la mayor parte del trabajo preliminar para rastrear esto."
          }
        ],
        "id": "CVE-2023-54276",
        "lastModified": "2026-06-17T06:47:08.507",
        "metrics": {},
        "published": "2025-12-30T13:16:16.537",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/3025d489f9c8984d1bf5916c4a20097ed80fca5c"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/66a178177b2b3bb1d71e854c5e7bbb320eb0e566"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/768c408594b52d8531e1a8ab62e5620c19213e73"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/8549384d0f65981761fe2077d04fa2a8d37b54e0"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/ed9ab7346e908496816cffdecd46932035f66e2e"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Deferred"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-11-07T04:33:08+00:00",
      "cve": "CVE-2023-54276",
      "id": "CVE-2023-54276",
      "initial_release_date": "2023-01-01T00:00:00+00:00",
      "product_status:known_affected": "123",
      "product_status:known_not_affected": "77",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: nfsd: move init of percpu reply_cache_stats counters back to nfsd_init_net",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2023/cve-2023-54276.json",
      "version": "3"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.