{"id":"CVE-2026-64600","state":"PUBLISHED","title":"xfs: resample the data fork mapping after cycling ILOCK","description":"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 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.","publishedAt":"2026-07-23T05:46:56.149Z","updatedAt":"2026-10-19T20:48:43.886Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"dc11be133efca5fe3a2fb02b016dee825cc12f18","versionType":"git"},{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"b8c9aa832b52680ee40d6cab0efb081f9a69df05","versionType":"git"},{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"50f0012da1040f69a4e788cd9aed587c9a04983f","versionType":"git"},{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"e705d81a7193dd19e69b8e2bad4696d78a4ea075","versionType":"git"},{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"206c09b04dc5469c7ff14d8aceff2d47c88078d9","versionType":"git"},{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"44f891bc088958399eec27f7604928694aa35581","versionType":"git"},{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/xfs/xfs_reflink.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.11","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.11","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.96","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/xfs/xfs_reflink.c"]}],"references":["https://git.kernel.org/stable/c/dc11be133efca5fe3a2fb02b016dee825cc12f18","https://git.kernel.org/stable/c/b8c9aa832b52680ee40d6cab0efb081f9a69df05","https://git.kernel.org/stable/c/50f0012da1040f69a4e788cd9aed587c9a04983f","https://git.kernel.org/stable/c/e705d81a7193dd19e69b8e2bad4696d78a4ea075","https://git.kernel.org/stable/c/206c09b04dc5469c7ff14d8aceff2d47c88078d9","https://git.kernel.org/stable/c/44f891bc088958399eec27f7604928694aa35581","https://git.kernel.org/stable/c/2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7","https://cdn2.qualys.com/advisory/2026/07/22/RefluXFS.txt","http://www.openwall.com/lists/oss-security/2026/07/22/14","http://www.openwall.com/lists/oss-security/2026/07/22/18","http://www.openwall.com/lists/oss-security/2026/07/22/19","http://www.openwall.com/lists/oss-security/2026/07/31/3","http://www.openwall.com/lists/oss-security/2026/08/03/4","http://www.openwall.com/lists/oss-security/2026/08/03/8"],"weaknesses":["CWE-362"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64600.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64600","state":"PUBLISHED","datePublished":"2026-07-23T05:46:56.149Z","dateUpdated":"2026-10-19T20:48:43.886Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.799Z"},"containers":{"cna":{"title":"xfs: resample the data fork mapping after cycling ILOCK","descriptions":[{"lang":"en","value":"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 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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"dc11be133efca5fe3a2fb02b016dee825cc12f18","versionType":"git"},{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"b8c9aa832b52680ee40d6cab0efb081f9a69df05","versionType":"git"},{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"50f0012da1040f69a4e788cd9aed587c9a04983f","versionType":"git"},{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"e705d81a7193dd19e69b8e2bad4696d78a4ea075","versionType":"git"},{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"206c09b04dc5469c7ff14d8aceff2d47c88078d9","versionType":"git"},{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"44f891bc088958399eec27f7604928694aa35581","versionType":"git"},{"version":"3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5","status":"affected","lessThan":"2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/xfs/xfs_reflink.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.11","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.11","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.96","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/xfs/xfs_reflink.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/dc11be133efca5fe3a2fb02b016dee825cc12f18"},{"url":"https://git.kernel.org/stable/c/b8c9aa832b52680ee40d6cab0efb081f9a69df05"},{"url":"https://git.kernel.org/stable/c/50f0012da1040f69a4e788cd9aed587c9a04983f"},{"url":"https://git.kernel.org/stable/c/e705d81a7193dd19e69b8e2bad4696d78a4ea075"},{"url":"https://git.kernel.org/stable/c/206c09b04dc5469c7ff14d8aceff2d47c88078d9"},{"url":"https://git.kernel.org/stable/c/44f891bc088958399eec27f7604928694aa35581"},{"url":"https://git.kernel.org/stable/c/2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7"},{"url":"https://cdn2.qualys.com/advisory/2026/07/22/RefluXFS.txt"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - Exploitation uses local FICLONE and concurrent O_DIRECT write syscalls against an XFS filesystem.\nAC:L - The attacker controls both racing writers, can amplify the transaction-allocation window, and demonstrated exploitation typically succeeds within seconds.\nPR:L - A basic unprivileged local user needs only read access to the protected source and write access to a scratch file; no capabilities are required.\nUI:N - The attacker creates the reflink and triggers both sides of the race without any victim action.\nS:U - This is a standard local kernel-mediated privilege escalation affecting resources within the host operating system's existing security authority.\nC:H - Overwriting /etc/passwd or a readable SUID-root binary yields full root access and consequently unrestricted access to system-confidential data.\nI:H - The stale physical mapping provides attacker-controlled persistent writes into protected readable files while preserving their ownership and SUID metadata, enabling full root compromise.\nA:H - The attacker can persistently corrupt boot-critical binaries or configuration files and, after obtaining root, cause complete system unavailability."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:58:23.073Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"5.15.212"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"6.1.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"6.12.96"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"6.18.39"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"7.1.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/07/22/14"},{"url":"http://www.openwall.com/lists/oss-security/2026/07/22/18"},{"url":"http://www.openwall.com/lists/oss-security/2026/07/22/19"},{"url":"http://www.openwall.com/lists/oss-security/2026/07/31/3"},{"url":"http://www.openwall.com/lists/oss-security/2026/08/03/4"},{"url":"http://www.openwall.com/lists/oss-security/2026/08/03/8"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-08-03T20:31:20.507Z"}},{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-64600","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:43:31.132977Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-362","lang":"en","type":"CWE","description":"CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:48:43.886Z"}}]}}}