CVE-2021-47132 (GCVE-0-2021-47132)

Vulnerability from cvelistv5 – Published: 2024-03-15 20:14 – Updated: 2026-08-05 08:46
VLAI
Title
mptcp: fix sk_forward_memory corruption on retransmission
Summary
In the Linux kernel, the following vulnerability has been resolved: mptcp: fix sk_forward_memory corruption on retransmission MPTCP sk_forward_memory handling is a bit special, as such field is protected by the msk socket spin_lock, instead of the plain socket lock. Currently we have a code path updating such field without handling the relevant lock: __mptcp_retrans() -> __mptcp_clean_una_wakeup() Several helpers in __mptcp_clean_una_wakeup() will update sk_forward_alloc, possibly causing such field corruption, as reported by Matthieu. Address the issue providing and using a new variant of blamed function which explicitly acquires the msk spin lock.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-03-18 15:54 UTC
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25 , < b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3 (git)
Affected: 64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25 , < b5941f066b4ca331db225a976dae1d6ca8cf0ae3 (git)
Affected: 96db8ffef07516a6d7414b6988f2a4298a839977 (git)
Affected: 5.11.4 , < 5.12 (semver)
guessed Create a notification for this product.
Linux Linux Affected: 5.12
Unaffected: 0 , < 5.12 (semver)
Unaffected: 5.12.10 , ≤ 5.12.* (semver)
Unaffected: 5.13 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-47132",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-03-18T15:54:25.829185Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-06-04T17:14:35.969Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T05:24:40.145Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/b5941f066b4ca331db225a976dae1d6ca8cf0ae3"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mptcp/protocol.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3",
              "status": "affected",
              "version": "64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25",
              "versionType": "git"
            },
            {
              "lessThan": "b5941f066b4ca331db225a976dae1d6ca8cf0ae3",
              "status": "affected",
              "version": "64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "96db8ffef07516a6d7414b6988f2a4298a839977",
              "versionType": "git"
            },
            {
              "lessThan": "5.12",
              "status": "affected",
              "version": "5.11.4",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/mptcp/protocol.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.12"
            },
            {
              "lessThan": "5.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.12.*",
              "status": "unaffected",
              "version": "5.12.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.13",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.12.10",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.13",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.11.4",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix sk_forward_memory corruption on retransmission\n\nMPTCP sk_forward_memory handling is a bit special, as such field\nis protected by the msk socket spin_lock, instead of the plain\nsocket lock.\n\nCurrently we have a code path updating such field without handling\nthe relevant lock:\n\n__mptcp_retrans() -\u003e __mptcp_clean_una_wakeup()\n\nSeveral helpers in __mptcp_clean_una_wakeup() will update\nsk_forward_alloc, possibly causing such field corruption, as reported\nby Matthieu.\n\nAddress the issue providing and using a new variant of blamed function\nwhich explicitly acquires the msk spin lock."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The bug is in the MPTCP protocol path (net/mptcp/); a remote MPTCP peer can induce retransmission (withheld/delayed ACKs or loss) and concurrently send packets that update sk_forward_alloc in softirq, reaching the unlocked clean_una path.\nAC:L - The attacker controls both sides of the race\u2014triggering MPTCP-level retransmission while sending traffic that races on sk_forward_alloc under mptcp_data_lock\u2014so success does not depend on conditions outside attacker influence.\nPR:N - No local privileges are required; an unauthenticated remote peer of an MPTCP connection (e.g., client to an internet-facing MPTCP service) can drive the retransmission and concurrent RX accounting paths.\nUI:N - Exploitation needs no victim user action beyond an existing or attacker-initiated MPTCP session; packet timing alone triggers the race.\nS:U - Impact is confined to the vulnerable host kernel\u2019s socket memory accounting; there is no cross-boundary escape (VM/IOMMU/sandbox).\nC:N - The race only corrupts the sk_forward_alloc accounting counter; it does not provide an information disclosure or arbitrary read primitive.\nI:N - This is integer memory-accounting corruption (WARN_ON leftovers / reclaim imbalance), not an OOB write, UAF, or other primitive that yields controlled data modification or code execution.\nA:H - Corrupted sk_forward_alloc leads to sk_stream_kill_queues/inet_sock_destruct WARN_ON (and potential panic_on_warn) plus broken reclaim that can exhaust or mis-account socket memory, causing high availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:46:14.316Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3"
        },
        {
          "url": "https://git.kernel.org/stable/c/b5941f066b4ca331db225a976dae1d6ca8cf0ae3"
        }
      ],
      "title": "mptcp: fix sk_forward_memory corruption on retransmission",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47132",
    "datePublished": "2024-03-15T20:14:35.337Z",
    "dateReserved": "2024-03-04T18:12:48.840Z",
    "dateUpdated": "2026-08-05T08:46:14.316Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-47132",
      "date": "2026-09-28",
      "epss": "0.00483",
      "percentile": "0.39166"
    },
    "fkie_nvd": {
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix sk_forward_memory corruption on retransmission\n\nMPTCP sk_forward_memory handling is a bit special, as such field\nis protected by the msk socket spin_lock, instead of the plain\nsocket lock.\n\nCurrently we have a code path updating such field without handling\nthe relevant lock:\n\n__mptcp_retrans() -\u003e __mptcp_clean_una_wakeup()\n\nSeveral helpers in __mptcp_clean_una_wakeup() will update\nsk_forward_alloc, possibly causing such field corruption, as reported\nby Matthieu.\n\nAddress the issue providing and using a new variant of blamed function\nwhich explicitly acquires the msk spin lock."
        },
        {
          "lang": "es",
          "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: mptcp: corrige la corrupci\u00f3n de sk_forward_memory en la retransmisi\u00f3n El manejo de MPTCP sk_forward_memory es un poco especial, ya que dicho campo est\u00e1 protegido por el socket msk spin_lock, en lugar del bloqueo de socket simple. Actualmente tenemos una ruta de c\u00f3digo que actualiza dicho campo sin manejar el bloqueo relevante: __mptcp_retrans() -\u0026gt; __mptcp_clean_una_wakeup() Varios ayudantes en __mptcp_clean_una_wakeup() actualizar\u00e1n sk_forward_alloc, posiblemente causando dicha corrupci\u00f3n de campo, seg\u00fan lo informado por Matthieu. Solucione el problema proporcionando y utilizando una nueva variante de la funci\u00f3n culpada que adquiere expl\u00edcitamente el bloqueo de giro msk."
        }
      ],
      "id": "CVE-2021-47132",
      "lastModified": "2024-11-21T06:35:27.780",
      "published": "2024-03-15T21:15:07.690",
      "references": [
        {
          "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
          "url": "https://git.kernel.org/stable/c/b5941f066b4ca331db225a976dae1d6ca8cf0ae3"
        },
        {
          "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
          "url": "https://git.kernel.org/stable/c/b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "url": "https://git.kernel.org/stable/c/b5941f066b4ca331db225a976dae1d6ca8cf0ae3"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "url": "https://git.kernel.org/stable/c/b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3"
        }
      ],
      "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "vulnStatus": "Awaiting Analysis"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "net/mptcp/protocol.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3",
                    "status": "affected",
                    "version": "64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "b5941f066b4ca331db225a976dae1d6ca8cf0ae3",
                    "status": "affected",
                    "version": "64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25",
                    "versionType": "git"
                  },
                  {
                    "status": "affected",
                    "version": "96db8ffef07516a6d7414b6988f2a4298a839977",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "5.12",
                    "status": "affected",
                    "version": "5.11.4",
                    "versionType": "semver"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "net/mptcp/protocol.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "5.12"
                  },
                  {
                    "lessThan": "5.12",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.12.*",
                    "status": "unaffected",
                    "version": "5.12.10",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "5.13",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "C68A4290-9FFF-4037-9467-4FF878E3085F",
                    "versionEndExcluding": "5.12.10",
                    "versionStartIncluding": "5.12",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*",
                    "matchCriteriaId": "0CBAD0FC-C281-4666-AB2F-F8E6E1165DF7",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:*",
                    "matchCriteriaId": "96AC23B2-D46A-49D9-8203-8E1BEDCA8532",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:*",
                    "matchCriteriaId": "DA610E30-717C-4700-9F77-A3C9244F3BFD",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:*",
                    "matchCriteriaId": "1ECD33F5-85BE-430B-8F86-8D7BD560311D",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix sk_forward_memory corruption on retransmission\n\nMPTCP sk_forward_memory handling is a bit special, as such field\nis protected by the msk socket spin_lock, instead of the plain\nsocket lock.\n\nCurrently we have a code path updating such field without handling\nthe relevant lock:\n\n__mptcp_retrans() -\u003e __mptcp_clean_una_wakeup()\n\nSeveral helpers in __mptcp_clean_una_wakeup() will update\nsk_forward_alloc, possibly causing such field corruption, as reported\nby Matthieu.\n\nAddress the issue providing and using a new variant of blamed function\nwhich explicitly acquires the msk spin lock."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: mptcp: corrige la corrupci\u00f3n de sk_forward_memory en la retransmisi\u00f3n El manejo de MPTCP sk_forward_memory es un poco especial, ya que dicho campo est\u00e1 protegido por el socket msk spin_lock, en lugar del bloqueo de socket simple. Actualmente tenemos una ruta de c\u00f3digo que actualiza dicho campo sin manejar el bloqueo relevante: __mptcp_retrans() -\u0026gt; __mptcp_clean_una_wakeup() Varios ayudantes en __mptcp_clean_una_wakeup() actualizar\u00e1n sk_forward_alloc, posiblemente causando dicha corrupci\u00f3n de campo, seg\u00fan lo informado por Matthieu. Solucione el problema proporcionando y utilizando una nueva variante de la funci\u00f3n culpada que adquiere expl\u00edcitamente el bloqueo de giro msk."
          }
        ],
        "id": "CVE-2021-47132",
        "lastModified": "2026-08-04T10:16:47.977",
        "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"
            },
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.1,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.2,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2021-47132",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-03-18T15:54:25.829185Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2024-03-15T21:15:07.690",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/b5941f066b4ca331db225a976dae1d6ca8cf0ae3"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/b5941f066b4ca331db225a976dae1d6ca8cf0ae3"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Modified",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-787"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-04T20:10:07+00:00",
      "cve": "CVE-2021-47132",
      "id": "CVE-2021-47132",
      "initial_release_date": "2021-01-01T00:00:00+00:00",
      "product_status:known_affected": "42",
      "product_status:known_not_affected": "156",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: mptcp: fix sk_forward_memory corruption on retransmission",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-47132.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2025-10-07T02:17:24Z",
      "cve": "CVE-2021-47132",
      "id": "CVE-2021-47132",
      "initial_release_date": "2024-03-19T03:50:22Z",
      "product_status:known_not_affected": "238",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-47132",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-47132.json",
      "version": "17"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "providerMetadata": {
              "dateUpdated": "2024-08-04T05:24:40.145Z",
              "orgId": "af854a3a-2127-422b-91ae-364da2661108",
              "shortName": "CVE"
            },
            "references": [
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://git.kernel.org/stable/c/b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3"
              },
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://git.kernel.org/stable/c/b5941f066b4ca331db225a976dae1d6ca8cf0ae3"
              }
            ],
            "title": "CVE Program Container"
          },
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2021-47132",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2024-03-18T15:54:25.829185Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2024-05-23T19:01:18.403Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "net/mptcp/protocol.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3",
                  "status": "affected",
                  "version": "64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25",
                  "versionType": "git"
                },
                {
                  "lessThan": "b5941f066b4ca331db225a976dae1d6ca8cf0ae3",
                  "status": "affected",
                  "version": "64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25",
                  "versionType": "git"
                },
                {
                  "status": "affected",
                  "version": "96db8ffef07516a6d7414b6988f2a4298a839977",
                  "versionType": "git"
                },
                {
                  "lessThan": "5.12",
                  "status": "affected",
                  "version": "5.11.4",
                  "versionType": "semver"
                }
              ]
            },
            {
              "defaultStatus": "affected",
              "product": "Linux",
              "programFiles": [
                "net/mptcp/protocol.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "status": "affected",
                  "version": "5.12"
                },
                {
                  "lessThan": "5.12",
                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "5.12.*",
                  "status": "unaffected",
                  "version": "5.12.10",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "*",
                  "status": "unaffected",
                  "version": "5.13",
                  "versionType": "original_commit_for_fix"
                }
              ]
            }
          ],
          "cpeApplicability": [
            {
              "nodes": [
                {
                  "cpeMatch": [
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.12.10",
                      "versionStartIncluding": "5.12",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.13",
                      "versionStartIncluding": "5.12",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionStartIncluding": "5.11.4",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix sk_forward_memory corruption on retransmission\n\nMPTCP sk_forward_memory handling is a bit special, as such field\nis protected by the msk socket spin_lock, instead of the plain\nsocket lock.\n\nCurrently we have a code path updating such field without handling\nthe relevant lock:\n\n__mptcp_retrans() -\u003e __mptcp_clean_una_wakeup()\n\nSeveral helpers in __mptcp_clean_una_wakeup() will update\nsk_forward_alloc, possibly causing such field corruption, as reported\nby Matthieu.\n\nAddress the issue providing and using a new variant of blamed function\nwhich explicitly acquires the msk spin lock."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "baseScore": 7.5,
                "baseSeverity": "HIGH",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "scenarios": [
                {
                  "lang": "en",
                  "value": "AV:N - The bug is in the MPTCP protocol path (net/mptcp/); a remote MPTCP peer can induce retransmission (withheld/delayed ACKs or loss) and concurrently send packets that update sk_forward_alloc in softirq, reaching the unlocked clean_una path.\nAC:L - The attacker controls both sides of the race\u2014triggering MPTCP-level retransmission while sending traffic that races on sk_forward_alloc under mptcp_data_lock\u2014so success does not depend on conditions outside attacker influence.\nPR:N - No local privileges are required; an unauthenticated remote peer of an MPTCP connection (e.g., client to an internet-facing MPTCP service) can drive the retransmission and concurrent RX accounting paths.\nUI:N - Exploitation needs no victim user action beyond an existing or attacker-initiated MPTCP session; packet timing alone triggers the race.\nS:U - Impact is confined to the vulnerable host kernel\u2019s socket memory accounting; there is no cross-boundary escape (VM/IOMMU/sandbox).\nC:N - The race only corrupts the sk_forward_alloc accounting counter; it does not provide an information disclosure or arbitrary read primitive.\nI:N - This is integer memory-accounting corruption (WARN_ON leftovers / reclaim imbalance), not an OOB write, UAF, or other primitive that yields controlled data modification or code execution.\nA:H - Corrupted sk_forward_alloc leads to sk_stream_kill_queues/inet_sock_destruct WARN_ON (and potential panic_on_warn) plus broken reclaim that can exhaust or mis-account socket memory, causing high availability impact."
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-08-05T08:46:14.316Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
          "references": [
            {
              "url": "https://git.kernel.org/stable/c/b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3"
            },
            {
              "url": "https://git.kernel.org/stable/c/b5941f066b4ca331db225a976dae1d6ca8cf0ae3"
            }
          ],
          "title": "mptcp: fix sk_forward_memory corruption on retransmission",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2021-47132",
        "datePublished": "2024-03-15T20:14:35.337Z",
        "dateReserved": "2024-03-04T18:12:48.840Z",
        "dateUpdated": "2026-08-05T08:46:14.316Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.



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.