CVE-2021-47232

Status: ModifiedCritical (9.8)—
Severity9.8Critical · CVSS 3.1
Exploitation probability0.62 %higher than 49% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitNot knownno public code found

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

can: j1939: fix Use-after-Free, hold skb ref while in use

This patch fixes a Use-after-Free found by the syzbot.

The problem is that a skb is taken from the per-session skb queue, without incrementing the ref count. This leads to a Use-after-Free if the skb is taken concurrently from the session queue due to a CTS.

CVSS

Base score
9.8
Version
3.1
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days
0.62 %
Percentile among all scored CVEs
49
Score date
10/21/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

CWEs

References

Show 8 references

Raw JSON (NVD)

Show
{
  "id": "CVE-2021-47232",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2021-47232",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2024-05-28T19:03:26.982947Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      },
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 8.4,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 2.5
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "9d71dd0c70099914fcd063135da3c580865e924c",
              "lessThan": "22cba878abf646cd3a02ee7c8c2cef7afe66a256",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9d71dd0c70099914fcd063135da3c580865e924c",
              "lessThan": "509ab6bfdd0c76daebbad0f0af07da712116de22",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9d71dd0c70099914fcd063135da3c580865e924c",
              "lessThan": "1071065eeb33d32b7d98c2ce7591881ae7381705",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9d71dd0c70099914fcd063135da3c580865e924c",
              "lessThan": "2030043e616cab40f510299f09b636285e0a3678",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/can/j1939/transport.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.4"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.4",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.4.128",
              "versionType": "semver",
              "lessThanOrEqual": "5.4.*"
            },
            {
              "status": "unaffected",
              "version": "5.10.46",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.12.13",
              "versionType": "semver",
              "lessThanOrEqual": "5.12.*"
            },
            {
              "status": "unaffected",
              "version": "5.13",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/can/j1939/transport.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "affectedData": [
        {
          "cpes": [
            "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"
          ],
          "vendor": "linux",
          "product": "linux_kernel",
          "versions": [
            {
              "status": "affected",
              "version": "9d71dd0c7009",
              "lessThan": "22cba878abf6 ",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "cpes": [
            "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"
          ],
          "vendor": "linux",
          "product": "linux_kernel",
          "versions": [
            {
              "status": "affected",
              "version": "9d71dd0c7009",
              "lessThan": " 509ab6bfdd0c ",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "cpes": [
            "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"
          ],
          "vendor": "linux",
          "product": "linux_kernel",
          "versions": [
            {
              "status": "affected",
              "version": "9d71dd0c7009",
              "lessThan": "1071065eeb33 ",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "cpes": [
            "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"
          ],
          "vendor": "linux",
          "product": "linux_kernel",
          "versions": [
            {
              "status": "affected",
              "version": "9d71dd0c7009",
              "lessThan": "2030043e616c ",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "cpes": [
            "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"
          ],
          "vendor": "linux",
          "product": "linux_kernel",
          "versions": [
            {
              "status": "unaffected",
              "version": "5.4.128",
              "lessThan": "5.5",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "cpes": [
            "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"
          ],
          "vendor": "linux",
          "product": "linux_kernel",
          "versions": [
            {
              "status": "unaffected",
              "version": " 5.10.46",
              "lessThan": "5.11",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "cpes": [
            "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"
          ],
          "vendor": "linux",
          "product": "linux_kernel",
          "versions": [
            {
              "status": "unaffected",
              "version": "5.12.13",
              "lessThan": "5.13",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "cpes": [
            "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"
          ],
          "vendor": "linux",
          "product": "linux_kernel",
          "versions": [
            {
              "status": "unaffected",
              "version": "5.13"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "cpes": [
            "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"
          ],
          "vendor": "linux",
          "product": "linux_kernel",
          "versions": [
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.4",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unknown"
        },
        {
          "cpes": [
            "cpe:2.3:o:linux:linux_kernel:5.4:-:*:*:*:*:*:*"
          ],
          "vendor": "linux",
          "product": "linux_kernel",
          "versions": [
            {
              "status": "affected",
              "version": "5.4"
            }
          ],
          "defaultStatus": "unknown"
        }
      ]
    }
  ],
  "published": "2024-05-21T15:15:12.557",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1071065eeb33d32b7d98c2ce7591881ae7381705",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2030043e616cab40f510299f09b636285e0a3678",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/22cba878abf646cd3a02ee7c8c2cef7afe66a256",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/509ab6bfdd0c76daebbad0f0af07da712116de22",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1071065eeb33d32b7d98c2ce7591881ae7381705",
      "tags": [
        "Patch"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/2030043e616cab40f510299f09b636285e0a3678",
      "tags": [
        "Patch"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/22cba878abf646cd3a02ee7c8c2cef7afe66a256",
      "tags": [
        "Patch"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/509ab6bfdd0c76daebbad0f0af07da712116de22",
      "tags": [
        "Patch"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: j1939: fix Use-after-Free, hold skb ref while in use\n\nThis patch fixes a Use-after-Free found by the syzbot.\n\nThe problem is that a skb is taken from the per-session skb queue,\nwithout incrementing the ref count. This leads to a Use-after-Free if\nthe skb is taken concurrently from the session queue due to a CTS."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: can: j1939: corrige Use-after-Free, mantenga presionada la referencia skb mientras está en uso. Este parche corrige un Use-after-Free encontrado por syzbot. El problema es que se toma un skb de la cola de skb por sesión, sin incrementar el recuento de referencias. Esto conduce a un use after free si el skb se toma simultáneamente de la cola de sesión debido a un CTS."
    }
  ],
  "lastModified": "2026-08-04T10:16:53.793",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "8C2A72CA-7A16-4ACC-8D7D-6132A9D8B054",
              "versionEndExcluding": "5.4.128",
              "versionStartIncluding": "5.4"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "59455D13-A902-42E1-97F7-5ED579777193",
              "versionEndExcluding": "5.10.46",
              "versionStartIncluding": "5.5"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "7806E7E5-6D4F-4E18-81C1-79B3C60EE855",
              "versionEndExcluding": "5.12.13",
              "versionStartIncluding": "5.11"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "0CBAD0FC-C281-4666-AB2F-F8E6E1165DF7"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "96AC23B2-D46A-49D9-8203-8E1BEDCA8532"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "DA610E30-717C-4700-9F77-A3C9244F3BFD"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "1ECD33F5-85BE-430B-8F86-8D7BD560311D"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "CF351855-2437-4CF5-AD7C-BDFA51F27683"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc6:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "25A855BA-2118-44F2-90EF-EBBB12AF51EF"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}