{"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"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64600.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-64600"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2498915"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64600"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64600"},{"url":"https://access.redhat.com/errata/RHSA-2026:41062"},{"url":"https://access.redhat.com/errata/RHSA-2026:39494"},{"url":"https://access.redhat.com/errata/RHBA-2026:41013"},{"url":"https://access.redhat.com/errata/RHSA-2026:41063"},{"url":"https://access.redhat.com/errata/RHSA-2026:40425"},{"url":"https://access.redhat.com/errata/RHBA-2026:39332"},{"url":"https://access.redhat.com/errata/RHSA-2026:46951"},{"url":"https://access.redhat.com/errata/RHSA-2026:39179"},{"url":"https://access.redhat.com/errata/RHSA-2026:47998"},{"url":"https://access.redhat.com/errata/RHSA-2026:39984"},{"url":"https://access.redhat.com/errata/RHBA-2026:41254"},{"url":"https://access.redhat.com/errata/RHSA-2026:41229"},{"url":"https://access.redhat.com/errata/RHSA-2026:48016"},{"url":"https://access.redhat.com/errata/RHSA-2026:47997"},{"url":"https://access.redhat.com/errata/RHSA-2026:47984"},{"url":"https://access.redhat.com/errata/RHSA-2026:47983"},{"url":"https://access.redhat.com/errata/RHSA-2026:47981"},{"url":"https://access.redhat.com/errata/RHSA-2026:39180"}],"tags":["nvd","exploit-available","csaf","vex","red-hat","cve.org"],"epss":0.00467,"epssPercentile":0.40254,"ingestedAt":"2026-07-27T06:16:48.977Z","exploits":{"github":10,"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":"2026-10-27T19:07:31.004Z"},"exploitAvailable":true,"vendor":"Red Hat","product":"Red Hat Enterprise Linux BaseOS E4S (v.9.4)","affected":["enterprise_linux_for_nvidia 26","enterprise_linux_appstream_eus_v_10_0","enterprise_linux_appstream_v_10","enterprise_linux_appstream_e4s_v_9_2","enterprise_linux_appstream_e4s_v_9_4","enterprise_linux_appstream_eus_v_9_6","enterprise_linux_appstream_v_9","enterprise_linux_baseos_eus_v_10_0","enterprise_linux_baseos_v_10","enterprise_linux_baseos_v_8","enterprise_linux_baseos_aus_v_8_4","enterprise_linux_baseos_eus_extension_v_8_4","enterprise_linux_baseos_aus_v_8_6","enterprise_linux_baseos_eus_extension_v_8_6","enterprise_linux_baseos_e4s_v_8_8","enterprise_linux_baseos_tus_v_8_8","enterprise_linux_baseos_e4s_v_9_2","enterprise_linux_baseos_e4s_v_9_4","enterprise_linux_baseos_eus_v_9_6","enterprise_linux_baseos_v_9","enterprise_linux_codeready_linux_builder_eus_v_10_0","enterprise_linux_codeready_linux_builder_v_10","enterprise_linux_crb_v_8","codeready_linux_builder_eus_v_9_6","enterprise_linux_codeready_linux_builder_v_9","enterprise_linux_real_time_for_nfv_eus_v_10_0","enterprise_linux_real_time_for_nfv_v_10","enterprise_linux_nfv_v_8","enterprise_linux_real_time_for_nfv_e4s_v_9_4","enterprise_linux_real_time_for_nfv_eus_v_9_6","enterprise_linux_real_time_for_nfv_v_9","enterprise_linux_real_time_eus_v_10_0","enterprise_linux_real_time_v_10","enterprise_linux_rt_v_8","enterprise_linux_real_time_e4s_v_9_4","enterprise_linux_real_time_eus_v_9_6","enterprise_linux_real_time_v_9"],"patched":["enterprise_linux_appstream_eus_v_10_0","enterprise_linux_appstream_v_10","enterprise_linux_appstream_e4s_v_9_2","enterprise_linux_appstream_e4s_v_9_4","enterprise_linux_appstream_eus_v_9_6","enterprise_linux_appstream_v_9","enterprise_linux_baseos_eus_v_10_0","enterprise_linux_baseos_v_10","enterprise_linux_baseos_v_8","enterprise_linux_baseos_aus_v_8_4","enterprise_linux_baseos_eus_extension_v_8_4","enterprise_linux_baseos_aus_v_8_6","enterprise_linux_baseos_eus_extension_v_8_6","enterprise_linux_baseos_e4s_v_8_8","enterprise_linux_baseos_tus_v_8_8","enterprise_linux_baseos_e4s_v_9_2","enterprise_linux_baseos_e4s_v_9_4","enterprise_linux_baseos_eus_v_9_6","enterprise_linux_baseos_v_9","enterprise_linux_codeready_linux_builder_eus_v_10_0","enterprise_linux_codeready_linux_builder_v_10","enterprise_linux_crb_v_8","codeready_linux_builder_eus_v_9_6","enterprise_linux_codeready_linux_builder_v_9","enterprise_linux_real_time_for_nfv_eus_v_10_0","enterprise_linux_real_time_for_nfv_v_10","enterprise_linux_nfv_v_8","enterprise_linux_real_time_for_nfv_e4s_v_9_4","enterprise_linux_real_time_for_nfv_eus_v_9_6","enterprise_linux_real_time_for_nfv_v_9","enterprise_linux_real_time_eus_v_10_0","enterprise_linux_real_time_v_10","enterprise_linux_rt_v_8","enterprise_linux_real_time_e4s_v_9_4","enterprise_linux_real_time_eus_v_9_6","enterprise_linux_real_time_v_9"],"cwe":["CWE-362"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:43:31.132977Z"},"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.\n\n## Vendor advisories\n\n- **RHSA-2026:41062** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux BaseOS EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0), Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0), Red Hat Enterprise Linux Real Time EUS (v. 10.0) · released 2026-07-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:41062)\n- **RHSA-2026:39494** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), Red Hat Enterprise Linux Real Time (v. 10) · released 2026-07-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:39494)\n- **RHBA-2026:41013** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.2), Red Hat Enterprise Linux BaseOS E4S (v.9.2) · released 2026-07-16 · [advisory](https://access.redhat.com/errata/RHBA-2026:41013)\n- **RHSA-2026:41063** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4), Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4), Red Hat Enterprise Linux Real Time E4S (v.9.4) · released 2026-07-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:41063)\n- **RHSA-2026:40425** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v.9.6), Red Hat Enterprise Linux BaseOS EUS (v.9.6), Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6), Red Hat Enterprise Linux Real Time EUS (v.9.6) · released 2026-07-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:40425)\n- **RHBA-2026:39332** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-07-14 · [advisory](https://access.redhat.com/errata/RHBA-2026:39332)\n- **RHSA-2026:46951** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-07-27 · [advisory](https://access.redhat.com/errata/RHSA-2026:46951)\n- **RHSA-2026:39179** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-07-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:39179)\n- **RHSA-2026:47998** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8) · released 2026-07-29 · [advisory](https://access.redhat.com/errata/RHSA-2026:47998)\n- **RHSA-2026:39984** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS AUS (v.8.4), Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) · released 2026-07-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:39984)\n- **RHBA-2026:41254** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS AUS (v.8.6), Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) · released 2026-07-17 · [advisory](https://access.redhat.com/errata/RHBA-2026:41254)\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux for NVIDIA 26 · no fix planned: Red Hat Enterprise Linux for NVIDIA 26 · updated 2026-09-25 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64600.json)","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"}]}