ntfs: fix off-by-one page overflow in ntfs_decompress()

{
  "id": "ebfb6d4a5470eee2292835408c5eb6ccb14d87d9549e2e34904ba467b1fbffcd",
  "url": "https://osv.dev/vulnerability/CVE-2026-90118",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ntfs: fix off-by-one page overflow in ntfs_decompress()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ntfs: fix off-by-one page overflow in ntfs_decompress() The per-token range check in ntfs_decompress() uses if (cb >= cb_sb_end || dp_addr > dp_sb_end) break; so dp_addr == dp_sb_end falls through to the symbol copy `*dp_addr++ = *cb++`, writing one byte past the destination page. Since NTFS_SB_SIZE == PAGE_SIZE the destination is a single page, so the byte lands in the adjacent page, and *dest_ofs is left one past the sub-block end (the later `*dest_ofs &= ~PAGE_MASK` then yields 1, not 0, so the page is never finalized and later sub-blocks keep writing further past it). A corrupted compressed $DATA attribute thus produces a bounded run of out-of-bounds writes when the file is read. Break as soon as dp_addr reaches dp_sb_end; a full sub-block still completes, as its final copy advances dp_addr to exactly dp_sb_end.",
    "evidence": "osv:CVE-2026-90118",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.2.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-90118",
      "aliases": [
        "CVE-2026-90118"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "1e9ea7e04472d4e5e12e58c881eaacfb3e49b669"
                },
                {
                  "fixed": "b42644e425fed4a5cd6c88372655da5c1b52c666"
                },
                {
                  "fixed": "98716c9fce21f6c8a9d71e08cf53e7504fa562f4"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90118.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.1.0"
                },
                {
                  "fixed": "7.2.6"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90118.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:28.778754129Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/98716c9fce21f6c8a9d71e08cf53e7504fa562f4",
        "https://git.kernel.org/stable/c/b42644e425fed4a5cd6c88372655da5c1b52c666",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90118.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90118",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90118.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90118",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 495795,
  "published_at": "2026-09-17T16:06:23.333+00:00"
}