{"id":"CVE-2026-64533","title":"fs/ntfs3: validate lcns_follow in log_replay conversion","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: validate lcns_follow in log_replay conversion\n\nlog_replay() converts DIR_PAGE_ENTRY_32 records into DIR_PAGE_ENTRY\nrecords when replaying version 0 restart ta…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < ca343a99806b4fc8e27c48f08be3445c5fcd1445","Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < ddfc8683e1a627dbf1b83bacf8961443dd654258","Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 57c071e2c4f30b9c6f5aacb6679aab1269fbae99","Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 159f694d682e4215b3822ae31ed3a4631628fe55","Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 7adb38279812c9c06b0e3fa7382f4d7887f3fa2d","Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 32b9f8733feb241627fa5f564b1a99b5cae974c5","Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 6a4c53a2e26a865565bd6a460961e8d6fcb32329","Linux 5.15"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:41:51.439492Z"},"published":"2026-07-27","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:42:40.223Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-64533","references":[{"url":"https://git.kernel.org/stable/c/ca343a99806b4fc8e27c48f08be3445c5fcd1445"},{"url":"https://git.kernel.org/stable/c/ddfc8683e1a627dbf1b83bacf8961443dd654258"},{"url":"https://git.kernel.org/stable/c/57c071e2c4f30b9c6f5aacb6679aab1269fbae99"},{"url":"https://git.kernel.org/stable/c/159f694d682e4215b3822ae31ed3a4631628fe55"},{"url":"https://git.kernel.org/stable/c/7adb38279812c9c06b0e3fa7382f4d7887f3fa2d"},{"url":"https://git.kernel.org/stable/c/32b9f8733feb241627fa5f564b1a99b5cae974c5"},{"url":"https://git.kernel.org/stable/c/6a4c53a2e26a865565bd6a460961e8d6fcb32329"}],"tags":["cve.org"],"epss":0.00135,"epssPercentile":0.02641,"ingestedAt":"2026-10-16T17:24:46.826Z","slug":"CVE-2026-64533","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: validate lcns_follow in log_replay conversion\n\nlog_replay() converts DIR_PAGE_ENTRY_32 records into DIR_PAGE_ENTRY\nrecords when replaying version 0 restart tables.\n\nDuring this conversion, the memmove() length is derived directly from\nthe on-disk lcns_follow field:\n\n\tmemmove(&dp->vcn, &dp0->vcn_low,\n\t\t2 * sizeof(u64) +\n\t\t\t\tle32_to_cpu(dp->lcns_follow) * sizeof(u64));\n\ncheck_rstbl() validates restart table structure, but does not constrain\nper-entry lcns_follow values relative to the entry size. A malformed\nfilesystem image can provide an oversized lcns_follow value, causing\nthe conversion memmove() to access memory beyond the bounds of the\nallocated restart table buffer.\n\nThe same field is later used to bound iteration over page_lcns[],\nso validating lcns_follow during conversion also prevents downstream\nout-of-bounds access from the same malformed metadata.\n\nCompute the maximum valid lcns_follow from the already-validated\nrestart table entry size and reject entries that exceed this bound.\nReuse the existing t16/t32 scratch variables already declared in\nlog_replay() to avoid introducing new declarations.\n\n[almaz.alexandrovich@paragon-software.com: fixed the conflicts]\n\n## Affected\n\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < ca343a99806b4fc8e27c48f08be3445c5fcd1445`\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < ddfc8683e1a627dbf1b83bacf8961443dd654258`\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 57c071e2c4f30b9c6f5aacb6679aab1269fbae99`\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 159f694d682e4215b3822ae31ed3a4631628fe55`\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 7adb38279812c9c06b0e3fa7382f4d7887f3fa2d`\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 32b9f8733feb241627fa5f564b1a99b5cae974c5`\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 6a4c53a2e26a865565bd6a460961e8d6fcb32329`\n- `Linux 5.15`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}