{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "ca06197382bde0a3bc20215595d1c9ce20c6e341"
            },
            {
              "fixed": "72a2589d82eb001c94b74bcfe6f9a599bd9bef60"
            },
            {
              "fixed": "fae76a94b35ee8c0e2eb6f64caca01d75c6d34e4"
            },
            {
              "fixed": "cf85180b8a015029ee147694eaf4e0b3537e9432"
            },
            {
              "fixed": "ce4736c1e6c4cfbf1ac409a8c328a0b69546c9a0"
            },
            {
              "fixed": "727bf7783a2936ffd55c628dddfd69343e511dcf"
            },
            {
              "fixed": "33c0b96d7e1672be1de0053786637ea46fb81507"
            },
            {
              "fixed": "c8e041c68c0bbb73aa62371ee63947bb6949d8b2"
            },
            {
              "fixed": "3a1230e7b043c62737b05a3e9275ca83a43ad20a"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.7.0"
            },
            {
              "fixed": "5.10.261"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.212"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.178"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.145"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.96"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.39"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64296.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nexfat: bound uniname advance in exfat_find_dir_entry()\n\nIn exfat_find_dir_entry(), each TYPE_EXTEND (file name) entry advances the\noutput pointer by a fixed amount while the loop guard only tracks the\naccumulated name length:\n\n\tif (++order == 2)\n\t\tuniname = p_uniname-\u003ename;\n\telse\n\t\tuniname += EXFAT_FILE_NAME_LEN;\n\tlen = exfat_extract_uni_name(ep, entry_uniname);\n\tname_len += len;\n\tunichar = *(uniname+len);\n\t*(uniname+len) = 0x0;\n\nuniname grows by EXFAT_FILE_NAME_LEN (15) per name entry, but name_len\ngrows only by the actual extracted length, which is shorter when a name\nfragment contains an early NUL.  The only guard is\n`name_len \u003e= MAX_NAME_LENGTH`, so a crafted directory with many short\nname fragments lets uniname run far past the\np_uniname-\u003ename[MAX_NAME_LENGTH + 3] buffer while name_len stays small,\ncausing an out-of-bounds read and write at *(uniname+len).\n\nThe sibling extractor exfat_get_uniname_from_ext_entry() already stops\non a short fragment (the lockstep `len != EXFAT_FILE_NAME_LEN` guard\nadded in commit d42334578eba (\"exfat: check if filename entries exceeds\nmax filename length\")); exfat_find_dir_entry() never got the\nequivalent.  Track the per-entry write offset as a count and reject a\nfragment once the offset, or the offset plus the extracted length, would\nexceed MAX_NAME_LENGTH, before forming the output pointer.",
  "id": "CVE-2026-64296",
  "modified": "2026-07-28T03:55:53.197727175Z",
  "published": "2026-07-25T08:49:33.847Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/33c0b96d7e1672be1de0053786637ea46fb81507"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3a1230e7b043c62737b05a3e9275ca83a43ad20a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/727bf7783a2936ffd55c628dddfd69343e511dcf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/72a2589d82eb001c94b74bcfe6f9a599bd9bef60"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c8e041c68c0bbb73aa62371ee63947bb6949d8b2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ce4736c1e6c4cfbf1ac409a8c328a0b69546c9a0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cf85180b8a015029ee147694eaf4e0b3537e9432"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fae76a94b35ee8c0e2eb6f64caca01d75c6d34e4"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64296.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64296"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "exfat: bound uniname advance in exfat_find_dir_entry()"
}