FKIE_CVE-2020-36791

Vulnerability from fkie_nvd - Published: 2025-05-07 14:15 - Updated: 2026-08-04 10:16
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net_sched: keep alloc_hash updated after hash allocation In commit 599be01ee567 ("net_sched: fix an OOB access in cls_tcindex") I moved cp->hash calculation before the first tcindex_alloc_perfect_hash(), but cp->alloc_hash is left untouched. This difference could lead to another out of bound access. cp->alloc_hash should always be the size allocated, we should update it after this tcindex_alloc_perfect_hash().
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://blog.cdthoughts.ch/2021/03/16/syzbot-bug.htmlThird Party Advisory
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0d1c3530e1bd38382edef72591b78e877e0edcd3Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/557d015ffb27b672e24e6ad141fd887783871dc2Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9f8b6c44be178c2498a00b270872a6e30e7c8266Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bd3ee8fb6371b45c71c9345cc359b94da2ddefa9Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c4453d2833671e3a9f6bd52f0f581056c3736386Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d23faf32e577922b6da20bf3740625c1105381bfPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d6cdc5bb19b595486fb2e6661e5138d73a57f454Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://syzkaller.appspot.com/bug?id=ea260693da894e7b078d18fca2c9c0a19b457534Issue Tracking
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 5.6
linux linux_kernel 5.6
linux linux_kernel 5.6
linux linux_kernel 5.6
linux linux_kernel 5.6
linux linux_kernel 5.6
linux linux_kernel 5.6
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sched/cls_tcindex.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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            },
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            },
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              "versionType": "git"
            },
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              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "2c66ff8d08f81bcf8e8cb22e31e39c051b15336a",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "599be01ee567b61f4471ee8078870847d0a11e8e",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sched/cls_tcindex.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "4.4.218",
              "status": "affected",
              "version": "4.4.214",
              "versionType": "semver"
            },
            {
              "lessThan": "4.9.218",
              "status": "affected",
              "version": "4.9.214",
              "versionType": "semver"
            },
            {
              "lessThan": "4.14.175",
              "status": "affected",
              "version": "4.14.171",
              "versionType": "semver"
            },
            {
              "lessThan": "4.19.114",
              "status": "affected",
              "version": "4.19.103",
              "versionType": "semver"
            },
            {
              "lessThan": "5.4.29",
              "status": "affected",
              "version": "5.4.19",
              "versionType": "semver"
            },
            {
              "lessThan": "5.5.14",
              "status": "affected",
              "version": "5.5.3",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet_sched: keep alloc_hash updated after hash allocation\n\nIn commit 599be01ee567 (\"net_sched: fix an OOB access in cls_tcindex\")\nI moved cp-\u003ehash calculation before the first\ntcindex_alloc_perfect_hash(), but cp-\u003ealloc_hash is left untouched.\nThis difference could lead to another out of bound access.\n\ncp-\u003ealloc_hash should always be the size allocated, we should\nupdate it after this tcindex_alloc_perfect_hash()."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net_sched: mantener alloc_hash actualizado tras la asignaci\u00f3n de hash. En el commit 599be01ee567 (\"net_sched: corregir un acceso OOB en cls_tcindex\"), se movi\u00f3 el c\u00e1lculo de cp-\u0026gt;hash antes del primer tcindex_alloc_perfect_hash(), pero se mantuvo intacto. Esta diferencia podr\u00eda provocar otro acceso fuera de los l\u00edmites. cp-\u0026gt;alloc_hash siempre debe tener el tama\u00f1o asignado; debemos actualizarlo despu\u00e9s de este tcindex_alloc_perfect_hash()."
    }
  ],
  "id": "CVE-2020-36791",
  "lastModified": "2026-08-04T10:16:35.580",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "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"
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        "exploitabilityScore": 1.8,
        "impactScore": 5.2,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2025-05-07T14:15:28.513",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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      ],
      "url": "https://blog.cdthoughts.ch/2021/03/16/syzbot-bug.html"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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      "tags": [
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      "url": "https://syzkaller.appspot.com/bug?id=ea260693da894e7b078d18fca2c9c0a19b457534"
    }
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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