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CVE-2026-64440

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: staging: rtl8723bs: fix OOB write in HT_caps_handler() HT_caps_handler() iterates pIE->length bytes and writes into HT_caps.u.HT_cap[], which is a fixed 26-byte array (sizeof struct HT_caps_element). Because pIE->length is a raw u8 from an over-the-air 802.11 AssocResponse frame and is never validated, a malicious AP can set it up to 255, causing up to 229 bytes of out-of-bounds writes into adjacent fields of struct mlme_ext_info. Truncate the iteration count to the size of HT_caps.u.HT_cap using umin() so that data from a longer-than-expected IE is silently ignored rather than written out of bounds, preserving interoperability with APs that pad the element. An early return on oversized IEs was considered but rejected: it would bypass the pmlmeinfo->HT_caps_enable = 1 assignment that precedes the loop, silently disabling HT mode for APs that append extra bytes to the HT Capabilities IE.

Severity
HIGH
CVSS score
8.1 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-07-25 10:17:28.547000
Last modified
2026-10-19 21:17:38.410000
View original CVE JSON 
{
  "id": "CVE-2026-64440",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-07-25T10:17:28.547",
  "lastModified": "2026-10-19T21:17:38.410",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nstaging: rtl8723bs: fix OOB write in HT_caps_handler()\n\nHT_caps_handler() iterates pIE->length bytes and writes into\nHT_caps.u.HT_cap[], which is a fixed 26-byte array (sizeof struct\nHT_caps_element). Because pIE->length is a raw u8 from an over-the-air\n802.11 AssocResponse frame and is never validated, a malicious AP can\nset it up to 255, causing up to 229 bytes of out-of-bounds writes into\nadjacent fields of struct mlme_ext_info.\n\nTruncate the iteration count to the size of HT_caps.u.HT_cap using\numin() so that data from a longer-than-expected IE is silently ignored\nrather than written out of bounds, preserving interoperability with APs\nthat pad the element. An early return on oversized IEs was considered\nbut rejected: it would bypass the pmlmeinfo->HT_caps_enable = 1\nassignment that precedes the loop, silently disabling HT mode for APs\nthat append extra bytes to the HT Capabilities IE."
    }
  ],
  "affected": [
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      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "drivers/staging/rtl8723bs/core/rtw_wlan_util.c"
          ],
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          "product": "Linux",
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
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              "version": "0",
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              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.15.212",
              "lessThanOrEqual": "5.15.*",
              "versionType": "semver",
              "status": "unaffected"
            },
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              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
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              "lessThanOrEqual": "6.6.*",
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            },
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            },
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              "status": "unaffected"
            },
            {
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              "status": "unaffected"
            },
            {
              "version": "7.2",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
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        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
          "baseScore": 8.1,
          "baseSeverity": "HIGH",
          "attackVector": "ADJACENT_NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.2
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-16T15:40:46.718780Z",
          "id": "CVE-2026-64440",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-787"
        }
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    },
    {
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      "type": "Secondary",
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          "value": "CWE-787"
        }
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    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
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}