← Back to CVE Explorer

CVE-2026-53391

Full vulnerability record from the local CVENow database.

Description

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.

Severity
HIGH
CVSS score
7.5 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-07-19 12:16:50.137000
Last modified
2026-10-19 20:19:17.817000
View original CVE JSON 
{
  "id": "CVE-2026-53391",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-07-19T12:16:50.137",
  "lastModified": "2026-10-19T20:19:17.817",
  "vulnStatus": "Modified",
  "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, '.') to locate the port separator. Both decodes\nuse xdr_stream_decode_string_dup(), and the current code checks only\n\"nlen < 0\" / \"rlen < 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 \"< 0\" check does not catch this, and the next line is\nstrrchr(NULL, '.'), 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."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "fs/nfs/pnfs_nfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "lessThan": "76b94cbd32aacf36a641956385a852635c6802b9",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "lessThan": "c8e4e0c701d0192a2efb6df059c0f9e19678c23d",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "lessThan": "6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "lessThan": "427ab81a811dab4bca9d19f82eec5847ae42646e",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "lessThan": "012d37a568bfbb2c9686f03ade75560bc7139956",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "lessThan": "30aae62e50b4e074a90a9a5e15246548fbdc1182",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "6b7f3cf96364eaf597940cb5c68a682894829915",
              "lessThan": "41fe0f7b84f0cb822ae10ab08592996a592b2a25",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "fs/nfs/pnfs_nfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "4.0",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "4.0",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.15.211",
              "lessThanOrEqual": "5.15.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.177",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.144",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.95",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.38",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.1.3",
              "lessThanOrEqual": "7.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-16T15:30:09.630598Z",
          "id": "CVE-2026-53391",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ]
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "4.0",
              "versionEndExcluding": "5.15.211",
              "matchCriteriaId": "BC7A1900-CBD2-444F-A28F-7B64DBA66194"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "5.16",
              "versionEndExcluding": "6.1.177",
              "matchCriteriaId": "333C9E30-7FD4-46A2-94EF-C1AA1F3EE28B"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "6.2",
              "versionEndExcluding": "6.6.144",
              "matchCriteriaId": "C8AD3BC8-C843-423C-B9DB-CB52F67F578E"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "6.7",
              "versionEndExcluding": "6.12.95",
              "matchCriteriaId": "4E206B86-E0E3-4394-A93F-39F2D50A8AA8"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "6.13",
              "versionEndExcluding": "6.18.38",
              "matchCriteriaId": "FA591B28-5D62-449E-BDBE-3C9391BF070A"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "6.19",
              "versionEndExcluding": "7.1.3",
              "matchCriteriaId": "9526B150-E2B3-4C6F-8AE5-1AF92B75AD9E"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/012d37a568bfbb2c9686f03ade75560bc7139956",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/30aae62e50b4e074a90a9a5e15246548fbdc1182",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/41fe0f7b84f0cb822ae10ab08592996a592b2a25",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/427ab81a811dab4bca9d19f82eec5847ae42646e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/76b94cbd32aacf36a641956385a852635c6802b9",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/c8e4e0c701d0192a2efb6df059c0f9e19678c23d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    }
  ]
}