CVE-2026-90151 (GCVE-0-2026-90151)
Vulnerability from cvelistv5
Published
2026-09-17 16:06
Modified
2026-10-19 08:58
Severity ?
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: NFSv4: remove callback IDR entry on client allocation failure nfs4_alloc_client() allocates an NFSv4.0 callback identifier before it finishes setting up the client. If any later initialization step fails, the error path frees the nfs_client directly with nfs_free_client(). That bypasses nfs_put_client(), which is where the callback IDR entry is removed during normal teardown. A failed allocation can therefore leave cb_ident_idr pointing at a freed nfs_client. A later NFSv4.0 callback lookup by cb_ident would find the stale pointer and take a reference to it. Make the callback IDR removal helper callable by the allocation failure path, and remove the callback identifier before freeing the client. This was found by a local static-analysis checker for publish-before-free lifetime bugs and confirmed by manual inspection.
References
Impacted products
Vendor Product Version
Linux Linux Version: f4eecd5da3422e82e88e36c33cbd2595eebcacb1
Version: f4eecd5da3422e82e88e36c33cbd2595eebcacb1
Version: f4eecd5da3422e82e88e36c33cbd2595eebcacb1
Version: f4eecd5da3422e82e88e36c33cbd2595eebcacb1
Version: f4eecd5da3422e82e88e36c33cbd2595eebcacb1
Version: f4eecd5da3422e82e88e36c33cbd2595eebcacb1
Version: f4eecd5da3422e82e88e36c33cbd2595eebcacb1
Version: f4eecd5da3422e82e88e36c33cbd2595eebcacb1
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfs/client.c",
            "fs/nfs/internal.h",
            "fs/nfs/nfs4client.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
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              "status": "affected",
              "version": "f4eecd5da3422e82e88e36c33cbd2595eebcacb1",
              "versionType": "git"
            },
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              "status": "affected",
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              "versionType": "git"
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              "status": "affected",
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              "versionType": "git"
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            {
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              "status": "affected",
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfs/client.c",
            "fs/nfs/internal.h",
            "fs/nfs/nfs4client.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.38"
            },
            {
              "lessThan": "2.6.38",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.270",
                  "versionStartIncluding": "2.6.38",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.221",
                  "versionStartIncluding": "2.6.38",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.188",
                  "versionStartIncluding": "2.6.38",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "2.6.38",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "2.6.38",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "2.6.38",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "2.6.38",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "2.6.38",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4: remove callback IDR entry on client allocation failure\n\nnfs4_alloc_client() allocates an NFSv4.0 callback identifier before it\nfinishes setting up the client. If any later initialization step fails,\nthe error path frees the nfs_client directly with nfs_free_client(). That\nbypasses nfs_put_client(), which is where the callback IDR entry is\nremoved during normal teardown.\n\nA failed allocation can therefore leave cb_ident_idr pointing at a freed\nnfs_client. A later NFSv4.0 callback lookup by cb_ident would find the\nstale pointer and take a reference to it.\n\nMake the callback IDR removal helper callable by the allocation failure\npath, and remove the callback identifier before freeing the client.\n\nThis was found by a local static-analysis checker for publish-before-free\nlifetime bugs and confirmed by manual inspection."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - nfs4_find_client_ident() is called from nfs4_callback_compound() with hdr_arg.cb_ident taken by decode_compound_hdr_arg() from an NFSv4.0 CB_COMPOUND on the TCP callback listener that nfs4_callback_up_net() binds to INADDR_ANY via svc_xprt_create(); the remote peer supplies that identifier over routable TCP.\nAC:L - A malicious NFSv4.0 server keeps the callback service up, then forces a later nfs4_alloc_client() to fail after nfs_get_cb_ident_idr() by making rpc_create()/rpc_ping() fail in nfs_create_rpc_client() (nfs4_create_referral_server or nfs4_update_server to an RST-ing address), then sends CB_COMPOUND with the next sequential idr id; no uncontrolled race is required.\nPR:N - nfs4_find_client_ident() runs in nfs4_callback_compound() before check_gss_callback_principal(), and nfs_callback_authenticate() accepts RPC_AUTH_UNIX for CB_COMPOUND, so the peer needs no account or capability on the victim client.\nUI:N - The same peer returns NFS4ERR_MOVED so nfs4_schedule_migration_recovery() or a LOOKUP referral (nfs4_create_referral_server) runs nfs4_alloc_client() from the state manager or automount, then sends the CB_COMPOUND itself; no extra victim mount dialog or file-open is required.\nS:U - The UAF is of an nfs_client published in cb_ident_idr and freed by nfs_free_client(); impact stays in the host kernel and does not cross a VM, IOMMU, or guest/host boundary.\nC:H - nfs4_find_client_ident() does refcount_inc(\u0026clp-\u003ecl_count) on the nfs_client that nfs_free_client() already kfree_rcu\u0027d, so a stale cb_ident_idr pointer remains; reclaim of that heap object yields an arbitrary kernel read, as with other kernel UAFs.\nI:H - The same stale-IDR lookup is a use-after-free write (refcount_inc, then nfs_put_client list_del and field access in check_gss_callback_principal/process_op); spraying the freed nfs_client enables arbitrary write and control-flow hijack.\nA:H - refcount_inc on the kfree_rcu\u0027d nfs_client, or later dereference of cl_rpcclient left as ERR_PTR(-EINVAL) when nfs_create_rpc_client() failed, causes a kernel oops/panic even without a full exploit."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:58:50.239Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/68c721391b761dbe38d5b0094d2bb6e8489ad92b"
        },
        {
          "url": "https://git.kernel.org/stable/c/9bfdd0f591307b5198826a0e7a5b2f35f87acd2d"
        },
        {
          "url": "https://git.kernel.org/stable/c/7c4812eb96bdcafb31a65b12f2aa96659429d1d4"
        },
        {
          "url": "https://git.kernel.org/stable/c/fc95ca82d5ae598c428ab5a00ae69f8526d59371"
        },
        {
          "url": "https://git.kernel.org/stable/c/80b1c3d5a881f7d9081aa9f46da9742878a0f893"
        },
        {
          "url": "https://git.kernel.org/stable/c/3f2387e8bfbc4efda5d77c3a11a028d0a119c48f"
        },
        {
          "url": "https://git.kernel.org/stable/c/5891c03e150920618db0e9c4ea2d772abacdcfd1"
        },
        {
          "url": "https://git.kernel.org/stable/c/d05c2007b3d84ccba11dc6e9cb3202768cc72f14"
        }
      ],
      "title": "NFSv4: remove callback IDR entry on client allocation failure",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90151",
    "datePublished": "2026-09-17T16:06:44.987Z",
    "dateReserved": "2026-09-11T19:38:34.789Z",
    "dateUpdated": "2026-10-19T08:58:50.239Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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