Vulnerability-Lookup

CVE-2026-31404 (GCVE-0-2026-31404)

Vulnerability from cvelistv5 – Published: 2026-04-03 15:16 – Updated: 2026-04-03 15:16

Title

NFSD: Defer sub-object cleanup in export put callbacks

Summary

In the Linux kernel, the following vulnerability has been resolved: NFSD: Defer sub-object cleanup in export put callbacks svc_export_put() calls path_put() and auth_domain_put() immediately when the last reference drops, before the RCU grace period. RCU readers in e_show() and c_show() access both ex_path (via seq_path/d_path) and ex_client->name (via seq_escape) without holding a reference. If cache_clean removes the entry and drops the last reference concurrently, the sub-objects are freed while still in use, producing a NULL pointer dereference in d_path. Commit 2530766492ec ("nfsd: fix UAF when access ex_uuid or ex_stats") moved kfree of ex_uuid and ex_stats into the call_rcu callback, but left path_put() and auth_domain_put() running before the grace period because both may sleep and call_rcu callbacks execute in softirq context. Replace call_rcu/kfree_rcu with queue_rcu_work(), which defers the callback until after the RCU grace period and executes it in process context where sleeping is permitted. This allows path_put() and auth_domain_put() to be moved into the deferred callback alongside the other resource releases. Apply the same fix to expkey_put(), which has the identical pattern with ek_path and ek_client. A dedicated workqueue scopes the shutdown drain to only NFSD export release work items; flushing the shared system_unbound_wq would stall on unrelated work from other subsystems. nfsd_export_shutdown() uses rcu_barrier() followed by flush_workqueue() to ensure all deferred release callbacks complete before the export caches are destroyed. Reviwed-by: Jeff Layton <jlayton@kernel.org>

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/2829e80d29b627886…
	https://git.kernel.org/stable/c/f5ab1bec5fa18731e…
	https://git.kernel.org/stable/c/48db892356d6cb80f…

Impacted products

Vendor

Product

Version

Linux

Affected: c224edca7af028828e2ad866b61d731b5e72b46d , < 2829e80d29b627886d12b5ea40856d56b516e67d (git)
Affected: c224edca7af028828e2ad866b61d731b5e72b46d , < f5ab1bec5fa18731e0b1b1e60c9a68667ac73ea2 (git)
Affected: c224edca7af028828e2ad866b61d731b5e72b46d , < 48db892356d6cb80f6942885545de4a6dd8d2a29 (git)

Linux

Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 6.18.20 , ≤ 6.18.* (semver)
Unaffected: 6.19.10 , ≤ 6.19.* (semver)
Unaffected: 7.0-rc5 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/export.c",
            "fs/nfsd/export.h",
            "fs/nfsd/nfsctl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2829e80d29b627886d12b5ea40856d56b516e67d",
              "status": "affected",
              "version": "c224edca7af028828e2ad866b61d731b5e72b46d",
              "versionType": "git"
            },
            {
              "lessThan": "f5ab1bec5fa18731e0b1b1e60c9a68667ac73ea2",
              "status": "affected",
              "version": "c224edca7af028828e2ad866b61d731b5e72b46d",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "c224edca7af028828e2ad866b61d731b5e72b46d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/export.c",
            "fs/nfsd/export.h",
            "fs/nfsd/nfsctl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.20",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0-rc5",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.20",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.10",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0-rc5",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Defer sub-object cleanup in export put callbacks\n\nsvc_export_put() calls path_put() and auth_domain_put() immediately\nwhen the last reference drops, before the RCU grace period. RCU\nreaders in e_show() and c_show() access both ex_path (via\nseq_path/d_path) and ex_client-\u003ename (via seq_escape) without\nholding a reference. If cache_clean removes the entry and drops the\nlast reference concurrently, the sub-objects are freed while still\nin use, producing a NULL pointer dereference in d_path.\n\nCommit 2530766492ec (\"nfsd: fix UAF when access ex_uuid or\nex_stats\") moved kfree of ex_uuid and ex_stats into the\ncall_rcu callback, but left path_put() and auth_domain_put() running\nbefore the grace period because both may sleep and call_rcu\ncallbacks execute in softirq context.\n\nReplace call_rcu/kfree_rcu with queue_rcu_work(), which defers the\ncallback until after the RCU grace period and executes it in process\ncontext where sleeping is permitted. This allows path_put() and\nauth_domain_put() to be moved into the deferred callback alongside\nthe other resource releases. Apply the same fix to expkey_put(),\nwhich has the identical pattern with ek_path and ek_client.\n\nA dedicated workqueue scopes the shutdown drain to only NFSD\nexport release work items; flushing the shared\nsystem_unbound_wq would stall on unrelated work from other\nsubsystems. nfsd_export_shutdown() uses rcu_barrier() followed\nby flush_workqueue() to ensure all deferred release callbacks\ncomplete before the export caches are destroyed.\n\nReviwed-by: Jeff Layton \u003cjlayton@kernel.org\u003e"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-03T15:16:07.207Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2829e80d29b627886d12b5ea40856d56b516e67d"
        },
        {
          "url": "https://git.kernel.org/stable/c/f5ab1bec5fa18731e0b1b1e60c9a68667ac73ea2"
        },
        {
          "url": "https://git.kernel.org/stable/c/48db892356d6cb80f6942885545de4a6dd8d2a29"
        }
      ],
      "title": "NFSD: Defer sub-object cleanup in export put callbacks",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31404",
    "datePublished": "2026-04-03T15:16:07.207Z",
    "dateReserved": "2026-03-09T15:48:24.086Z",
    "dateUpdated": "2026-04-03T15:16:07.207Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-31404\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-04-03T16:16:39.643\",\"lastModified\":\"2026-04-07T13:20:55.200\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nNFSD: Defer sub-object cleanup in export put callbacks\\n\\nsvc_export_put() calls path_put() and auth_domain_put() immediately\\nwhen the last reference drops, before the RCU grace period. RCU\\nreaders in e_show() and c_show() access both ex_path (via\\nseq_path/d_path) and ex_client-\u003ename (via seq_escape) without\\nholding a reference. If cache_clean removes the entry and drops the\\nlast reference concurrently, the sub-objects are freed while still\\nin use, producing a NULL pointer dereference in d_path.\\n\\nCommit 2530766492ec (\\\"nfsd: fix UAF when access ex_uuid or\\nex_stats\\\") moved kfree of ex_uuid and ex_stats into the\\ncall_rcu callback, but left path_put() and auth_domain_put() running\\nbefore the grace period because both may sleep and call_rcu\\ncallbacks execute in softirq context.\\n\\nReplace call_rcu/kfree_rcu with queue_rcu_work(), which defers the\\ncallback until after the RCU grace period and executes it in process\\ncontext where sleeping is permitted. This allows path_put() and\\nauth_domain_put() to be moved into the deferred callback alongside\\nthe other resource releases. Apply the same fix to expkey_put(),\\nwhich has the identical pattern with ek_path and ek_client.\\n\\nA dedicated workqueue scopes the shutdown drain to only NFSD\\nexport release work items; flushing the shared\\nsystem_unbound_wq would stall on unrelated work from other\\nsubsystems. nfsd_export_shutdown() uses rcu_barrier() followed\\nby flush_workqueue() to ensure all deferred release callbacks\\ncomplete before the export caches are destroyed.\\n\\nReviwed-by: Jeff Layton \u003cjlayton@kernel.org\u003e\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/2829e80d29b627886d12b5ea40856d56b516e67d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/48db892356d6cb80f6942885545de4a6dd8d2a29\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f5ab1bec5fa18731e0b1b1e60c9a68667ac73ea2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}

GHSA-M9X4-X7J5-6V8X

Vulnerability from github – Published: 2026-04-03 18:31 – Updated: 2026-04-03 18:31

Details

In the Linux kernel, the following vulnerability has been resolved:

NFSD: Defer sub-object cleanup in export put callbacks

svc_export_put() calls path_put() and auth_domain_put() immediately when the last reference drops, before the RCU grace period. RCU readers in e_show() and c_show() access both ex_path (via seq_path/d_path) and ex_client->name (via seq_escape) without holding a reference. If cache_clean removes the entry and drops the last reference concurrently, the sub-objects are freed while still in use, producing a NULL pointer dereference in d_path.

Commit 2530766492ec ("nfsd: fix UAF when access ex_uuid or ex_stats") moved kfree of ex_uuid and ex_stats into the call_rcu callback, but left path_put() and auth_domain_put() running before the grace period because both may sleep and call_rcu callbacks execute in softirq context.

Replace call_rcu/kfree_rcu with queue_rcu_work(), which defers the callback until after the RCU grace period and executes it in process context where sleeping is permitted. This allows path_put() and auth_domain_put() to be moved into the deferred callback alongside the other resource releases. Apply the same fix to expkey_put(), which has the identical pattern with ek_path and ek_client.

A dedicated workqueue scopes the shutdown drain to only NFSD export release work items; flushing the shared system_unbound_wq would stall on unrelated work from other subsystems. nfsd_export_shutdown() uses rcu_barrier() followed by flush_workqueue() to ensure all deferred release callbacks complete before the export caches are destroyed.

Reviwed-by: Jeff Layton jlayton@kernel.org

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-31404"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-03T16:16:39Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Defer sub-object cleanup in export put callbacks\n\nsvc_export_put() calls path_put() and auth_domain_put() immediately\nwhen the last reference drops, before the RCU grace period. RCU\nreaders in e_show() and c_show() access both ex_path (via\nseq_path/d_path) and ex_client-\u003ename (via seq_escape) without\nholding a reference. If cache_clean removes the entry and drops the\nlast reference concurrently, the sub-objects are freed while still\nin use, producing a NULL pointer dereference in d_path.\n\nCommit 2530766492ec (\"nfsd: fix UAF when access ex_uuid or\nex_stats\") moved kfree of ex_uuid and ex_stats into the\ncall_rcu callback, but left path_put() and auth_domain_put() running\nbefore the grace period because both may sleep and call_rcu\ncallbacks execute in softirq context.\n\nReplace call_rcu/kfree_rcu with queue_rcu_work(), which defers the\ncallback until after the RCU grace period and executes it in process\ncontext where sleeping is permitted. This allows path_put() and\nauth_domain_put() to be moved into the deferred callback alongside\nthe other resource releases. Apply the same fix to expkey_put(),\nwhich has the identical pattern with ek_path and ek_client.\n\nA dedicated workqueue scopes the shutdown drain to only NFSD\nexport release work items; flushing the shared\nsystem_unbound_wq would stall on unrelated work from other\nsubsystems. nfsd_export_shutdown() uses rcu_barrier() followed\nby flush_workqueue() to ensure all deferred release callbacks\ncomplete before the export caches are destroyed.\n\nReviwed-by: Jeff Layton \u003cjlayton@kernel.org\u003e",
  "id": "GHSA-m9x4-x7j5-6v8x",
  "modified": "2026-04-03T18:31:23Z",
  "published": "2026-04-03T18:31:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31404"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2829e80d29b627886d12b5ea40856d56b516e67d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/48db892356d6cb80f6942885545de4a6dd8d2a29"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f5ab1bec5fa18731e0b1b1e60c9a68667ac73ea2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

FKIE_CVE-2026-31404

Vulnerability from fkie_nvd - Published: 2026-04-03 16:16 - Updated: 2026-04-07 13:20

Severity ?

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2829e80d29b627886d12b5ea40856d56b516e67d
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/48db892356d6cb80f6942885545de4a6dd8d2a29
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/f5ab1bec5fa18731e0b1b1e60c9a68667ac73ea2

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Defer sub-object cleanup in export put callbacks\n\nsvc_export_put() calls path_put() and auth_domain_put() immediately\nwhen the last reference drops, before the RCU grace period. RCU\nreaders in e_show() and c_show() access both ex_path (via\nseq_path/d_path) and ex_client-\u003ename (via seq_escape) without\nholding a reference. If cache_clean removes the entry and drops the\nlast reference concurrently, the sub-objects are freed while still\nin use, producing a NULL pointer dereference in d_path.\n\nCommit 2530766492ec (\"nfsd: fix UAF when access ex_uuid or\nex_stats\") moved kfree of ex_uuid and ex_stats into the\ncall_rcu callback, but left path_put() and auth_domain_put() running\nbefore the grace period because both may sleep and call_rcu\ncallbacks execute in softirq context.\n\nReplace call_rcu/kfree_rcu with queue_rcu_work(), which defers the\ncallback until after the RCU grace period and executes it in process\ncontext where sleeping is permitted. This allows path_put() and\nauth_domain_put() to be moved into the deferred callback alongside\nthe other resource releases. Apply the same fix to expkey_put(),\nwhich has the identical pattern with ek_path and ek_client.\n\nA dedicated workqueue scopes the shutdown drain to only NFSD\nexport release work items; flushing the shared\nsystem_unbound_wq would stall on unrelated work from other\nsubsystems. nfsd_export_shutdown() uses rcu_barrier() followed\nby flush_workqueue() to ensure all deferred release callbacks\ncomplete before the export caches are destroyed.\n\nReviwed-by: Jeff Layton \u003cjlayton@kernel.org\u003e"
    }
  ],
  "id": "CVE-2026-31404",
  "lastModified": "2026-04-07T13:20:55.200",
  "metrics": {},
  "published": "2026-04-03T16:16:39.643",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2829e80d29b627886d12b5ea40856d56b516e67d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/48db892356d6cb80f6942885545de4a6dd8d2a29"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f5ab1bec5fa18731e0b1b1e60c9a68667ac73ea2"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}

Sightings

Author	Source	Type	Date

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.

Detection rules are retrieved from Rulezet.

Action not permitted

CVE-2026-31404 (GCVE-0-2026-31404)

GHSA-M9X4-X7J5-6V8X

FKIE_CVE-2026-31404

Tags

Sightings

Nomenclature