{"id":"CVE-2026-64600","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfs: resample the data fork mapping after cycling ILOCK\n\nxfs_reflink_fill_{cow_hole,delalloc} are both presented with an inode,\na data fork mapping, and a cow fork mapp…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfs: resample the data fork mapping after cycling ILOCK\n\nxfs_reflink_fill_{cow_hole,delalloc} are both presented with an inode,\na data fork mapping, and a cow fork mapp…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","published":"2026-07-23","updated":"2026-07-27","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-64600","references":[{"url":"https://cdn2.qualys.com/advisory/2026/07/22/RefluXFS.txt","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/206c09b04dc5469c7ff14d8aceff2d47c88078d9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/44f891bc088958399eec27f7604928694aa35581","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/50f0012da1040f69a4e788cd9aed587c9a04983f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b8c9aa832b52680ee40d6cab0efb081f9a69df05","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/dc11be133efca5fe3a2fb02b016dee825cc12f18","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e705d81a7193dd19e69b8e2bad4696d78a4ea075","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"http://www.openwall.com/lists/oss-security/2026/07/22/14","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2026/07/22/18","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2026/07/22/19","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd","exploit-available"],"epss":0.00467,"epssPercentile":0.39507,"ingestedAt":"2026-07-27T06:16:48.977Z","exploits":{"github":9,"githubRepos":["https://github.com/0xBlackash/CVE-2026-64600","https://github.com/Debajyoti0-0/CVE-2026-64600","https://github.com/litosmartin/CVE-2026-64600-Refluxfs-PoC"],"checkedAt":"2026-09-21T15:30:07.587Z"},"exploitAvailable":true,"slug":"CVE-2026-64600","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nxfs: resample the data fork mapping after cycling ILOCK\n\nxfs_reflink_fill_{cow_hole,delalloc} are both presented with an inode,\na data fork mapping, and a cow fork mapping.  Unfortunately, these two\nhelpers cycle the ILOCK to grab a transaction, which means that the\nmappings are stale as soon as we reacquire the ILOCK.  Currently we\nrefresh the cow fork mapping by re-calling xfs_find_trim_cow_extent, but\nwe don't refresh the data fork mapping beforehand, which means that the\nxfs_bmap_trim_cow in that function queries the refcount btree about the\nwrong physical blocks and returns an inaccurate value in *shared.\n\nIf *shared is now false, the directio write proceeds with a stale data\nfork mapping.  Fix this by querying the data fork mapping if the\nsequence counter changes across the ILOCK cycle.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":55,"depthScoreParts":{"impact":42.9,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":5400,"id":"CVE-2026-64600","ts":1788887280479,"field":"exploit_available","old":"false","new":"true"},{"seq":4283,"id":"CVE-2026-64600","ts":1788886394186,"field":"exploit_available","old":"true","new":"false"},{"seq":3032,"id":"CVE-2026-64600","ts":1788883057829,"field":"exploit_available","old":"false","new":"true"},{"seq":2061,"id":"CVE-2026-64600","ts":1788882462291,"field":"exploit_available","old":"true","new":"false"},{"seq":1134,"id":"CVE-2026-64600","ts":1788881899372,"field":"exploit_available","old":"false","new":"true"}]}