CVE-2025-68761 (GCVE-0-2025-68761)

Vulnerability from cvelistv5 – Published: 2026-01-05 09:32 – Updated: 2026-08-05 12:11
VLAI
Title
hfs: fix potential use after free in hfs_correct_next_unused_CNID()
Summary
In the Linux kernel, the following vulnerability has been resolved: hfs: fix potential use after free in hfs_correct_next_unused_CNID() This code calls hfs_bnode_put(node) which drops the refcount and then dreferences "node" on the next line. It's only safe to use "node" when we're holding a reference so flip these two lines around.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7061 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: a06ec283e125e334155fe13005c76c9f484ce759 , < 40a1e0142096dd7dd6cb5373841222b528698588 (git)
Affected: a06ec283e125e334155fe13005c76c9f484ce759 , < c105e76bb17cf4b55fe89c6ad4f6a0e3972b5b08 (git)
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Linux Linux Affected: 6.18
Unaffected: 0 , < 6.18 (semver)
Unaffected: 6.18.2 , ≤ 6.18.* (semver)
Unaffected: 6.19 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/hfs/catalog.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "a06ec283e125e334155fe13005c76c9f484ce759",
              "versionType": "git"
            },
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              "status": "affected",
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              "versionType": "git"
            }
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        {
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          "product": "Linux",
          "programFiles": [
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          ],
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          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "6.18"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "6.18.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.19",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.2",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhfs: fix potential use after free in hfs_correct_next_unused_CNID()\n\nThis code calls hfs_bnode_put(node) which drops the refcount and then\ndreferences \"node\" on the next line.  It\u0027s only safe to use \"node\"\nwhen we\u0027re holding a reference so flip these two lines around."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable path is reached locally through unlink, rmdir, or an overwriting rename on a writable, already-mounted HFS filesystem.\nAC:L - An attacker can create thread-only catalog tail nodes, repeatedly delete the highest-CNID object, induce reclaim pressure, and heap-spray the freed node; no condition fundamentally outside attacker control is required.\nPR:L - Mounting HFS requires CAP_SYS_ADMIN in the initial user namespace, but an ordinary user with write and search permission on an existing HFS directory can trigger the vulnerable deletion path.\nUI:N - The attacker directly invokes the filesystem operations, requiring no action by another user once a writable HFS volume is available.\nS:U - Exploitation compromises the host kernel within the same security authority and does not inherently cross a virtualization or comparable isolation boundary.\nC:H - Reclaim and heap spraying can replace the freed B-tree node, after which attacker-controlled tree and page fields may be dereferenced, supporting kernel-memory disclosure.\nI:H - The use-after-free can progress beyond the initial stale prev read into reuse of attacker-sprayed pointer, refcount, and lock fields, supporting arbitrary memory modification or control-flow hijacking.\nA:H - Dereferencing a reclaimed node can cause a kernel oops or panic, while a manipulated traversal can also loop or corrupt critical HFS state."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:11:21.089Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/40a1e0142096dd7dd6cb5373841222b528698588"
        },
        {
          "url": "https://git.kernel.org/stable/c/c105e76bb17cf4b55fe89c6ad4f6a0e3972b5b08"
        }
      ],
      "title": "hfs: fix potential use after free in hfs_correct_next_unused_CNID()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-68761",
    "datePublished": "2026-01-05T09:32:33.814Z",
    "dateReserved": "2025-12-24T10:30:51.034Z",
    "dateUpdated": "2026-08-05T12:11:21.089Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-68761",
      "date": "2026-10-23",
      "epss": "0.00134",
      "percentile": "0.02631"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "fs/hfs/catalog.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "40a1e0142096dd7dd6cb5373841222b528698588",
                    "status": "affected",
                    "version": "a06ec283e125e334155fe13005c76c9f484ce759",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "c105e76bb17cf4b55fe89c6ad4f6a0e3972b5b08",
                    "status": "affected",
                    "version": "a06ec283e125e334155fe13005c76c9f484ce759",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "fs/hfs/catalog.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "6.18"
                  },
                  {
                    "lessThan": "6.18",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
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                    "status": "unaffected",
                    "version": "6.18.2",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "6.19",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhfs: fix potential use after free in hfs_correct_next_unused_CNID()\n\nThis code calls hfs_bnode_put(node) which drops the refcount and then\ndreferences \"node\" on the next line.  It\u0027s only safe to use \"node\"\nwhen we\u0027re holding a reference so flip these two lines around."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nhfs: correcci\u00f3n de posible uso despu\u00e9s de liberar en hfs_correct_next_unused_CNID()\n\nEste c\u00f3digo llama a hfs_bnode_put(node) lo que decrementa el contador de referencias y luego desreferencia \u0027node\u0027 en la siguiente l\u00ednea. Solo es seguro usar \u0027node\u0027 cuando mantenemos una referencia, as\u00ed que invierta estas dos l\u00edneas."
          }
        ],
        "id": "CVE-2025-68761",
        "lastModified": "2026-10-14T16:10:00.250",
        "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"
            }
          ]
        },
        "published": "2026-01-05T10:15:57.240",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/40a1e0142096dd7dd6cb5373841222b528698588"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/c105e76bb17cf4b55fe89c6ad4f6a0e3972b5b08"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Deferred"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-08-21T11:43:57+00:00",
      "cve": "CVE-2025-68761",
      "id": "CVE-2025-68761",
      "initial_release_date": "2025-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Kernel: Privilege escalation via use-after-free in HFS filesystem",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-68761.json",
      "version": "3"
    }
  }
}



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