FKIE_CVE-2026-53391

Vulnerability from fkie_nvd - Published: 2026-07-19 12:16 - Updated: 2026-07-20 15:16
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: NFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr nfs4_decode_mp_ds_addr() decodes the r_netid and r_addr opaques of a netaddr4 from a GETDEVICEINFO multipath-DS body, then immediately calls strrchr(buf, '.') to locate the port separator. Both decodes use xdr_stream_decode_string_dup(), and the current code checks only "nlen < 0" / "rlen < 0" before dereferencing the returned string. When the on-wire opaque has length zero, xdr_stream_decode_opaque_inline() returns 0 and xdr_stream_decode_string_dup() falls through to its "*str = NULL; return ret" tail, leaving buf NULL with a return value of 0. The "< 0" check does not catch this, and the next line is strrchr(NULL, '.'), a kernel NULL pointer dereference reachable from any pNFS-flexfile client mounted against a malicious or compromised metadata server. Reject the zero-length cases explicitly so the decoder fails with -EBADMSG (treated as a malformed GETDEVICEINFO body) instead of panicking the client.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/012d37a568bfbb2c9686f03ade75560bc7139956
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/30aae62e50b4e074a90a9a5e15246548fbdc1182
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/41fe0f7b84f0cb822ae10ab08592996a592b2a25
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/427ab81a811dab4bca9d19f82eec5847ae42646e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/76b94cbd32aacf36a641956385a852635c6802b9
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c8e4e0c701d0192a2efb6df059c0f9e19678c23d
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfs/pnfs_nfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "76b94cbd32aacf36a641956385a852635c6802b9",
              "status": "affected",
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "versionType": "git"
            },
            {
              "lessThan": "c8e4e0c701d0192a2efb6df059c0f9e19678c23d",
              "status": "affected",
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "versionType": "git"
            },
            {
              "lessThan": "6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea",
              "status": "affected",
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "versionType": "git"
            },
            {
              "lessThan": "427ab81a811dab4bca9d19f82eec5847ae42646e",
              "status": "affected",
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "versionType": "git"
            },
            {
              "lessThan": "012d37a568bfbb2c9686f03ade75560bc7139956",
              "status": "affected",
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "versionType": "git"
            },
            {
              "lessThan": "30aae62e50b4e074a90a9a5e15246548fbdc1182",
              "status": "affected",
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "versionType": "git"
            },
            {
              "lessThan": "41fe0f7b84f0cb822ae10ab08592996a592b2a25",
              "status": "affected",
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfs/pnfs_nfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.0"
            },
            {
              "lessThan": "4.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.211",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.177",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.144",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.95",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.38",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "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\nNFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr\n\nnfs4_decode_mp_ds_addr() decodes the r_netid and r_addr opaques of a\nnetaddr4 from a GETDEVICEINFO multipath-DS body, then immediately\ncalls strrchr(buf, \u0027.\u0027) to locate the port separator. Both decodes\nuse xdr_stream_decode_string_dup(), and the current code checks only\n\"nlen \u003c 0\" / \"rlen \u003c 0\" before dereferencing the returned string.\n\nWhen the on-wire opaque has length zero, xdr_stream_decode_opaque_inline()\nreturns 0 and xdr_stream_decode_string_dup() falls through to its\n\"*str = NULL; return ret\" tail, leaving buf NULL with a return value\nof 0. The \"\u003c 0\" check does not catch this, and the next line is\nstrrchr(NULL, \u0027.\u0027), a kernel NULL pointer dereference reachable from\nany pNFS-flexfile client mounted against a malicious or compromised\nmetadata server.\n\nReject the zero-length cases explicitly so the decoder fails with\n-EBADMSG (treated as a malformed GETDEVICEINFO body) instead of\npanicking the client."
    }
  ],
  "id": "CVE-2026-53391",
  "lastModified": "2026-07-20T15:16:41.693",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-19T12:16:50.137",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/012d37a568bfbb2c9686f03ade75560bc7139956"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/30aae62e50b4e074a90a9a5e15246548fbdc1182"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/41fe0f7b84f0cb822ae10ab08592996a592b2a25"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/427ab81a811dab4bca9d19f82eec5847ae42646e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/76b94cbd32aacf36a641956385a852635c6802b9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c8e4e0c701d0192a2efb6df059c0f9e19678c23d"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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