{"id":"CVE-2026-98975","revision":"642e409ec22544a593144e9aa24ffe9b","records":[{"revision":"642e409ec22544a593144e9aa24ffe9b","observedAt":"2026-10-24T16:17:04.479+00:00","statement":{"source":"cve-program","id":"CVE-2026-98975","aliases":[],"title":"xfs: stop exchanging reflink flags when exchanging mappings","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfs: stop exchanging reflink flags when exchanging mappings\n\nWhen an exchange covers both files from offset 0 to i_disk_size,\nxmi_can_exchange_reflink_flags() assumes every mapping moved and hands\nthe reflink flag over to the other file.\n\nThat assumption is wrong.  A file can still own shared blocks past\ni_disk_size, e.g. after EXCHANGE_RANGE_TO_EOF sets a smaller size\nwithout unmapping anything.  The flag is cleared anyway, and the next\nwrite to such a block happens in place instead of CoW, corrupting the\nother file that shares it.\n\nCommit a23eca88448e (\"xfs: fix exchange-range reflink flag clearing\nissue with INO1_WRITTEN\") fixed one instance of this.  Rather than add\nanother special case, stop moving the flags.\nxfs_exchmaps_ensure_reflink() already sets the flag on both inodes\nbefore the exchange, so both just keep it.\n\nNothing sets CLEAR_INO{1,2}_REFLINK anymore.  Intents logged by older\nkernels may still carry them; recovery already masks them off, so they\nstay in the log format mask and are ignored.\n\nXFS_IOC_SWAPEXT has the same problem: it moves the reflink flag from\none inode to the other along with the extents.  Just removing that is\nnot enough here: the exchange path flags both inodes up front in\nxfs_exchmaps_ensure_reflink(), but swapext has no such step, so the\ninode receiving the shared extents would be left without the flag.\nSet it on both inodes instead, and make sure both have a CoW fork,\nsince an inode with the reflink flag is expected to have one.\n\nThe flag now stays until FALLOC_FL_UNSHARE_RANGE, xfs_scrub, or a\ntruncate to zero removes it.","state":0,"publishedAt":"2026-10-23T12:19:48.379+00:00","modifiedAt":"2026-10-24T14:09:45.21+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/xfs/libxfs/xfs_exchmaps.c\",\n                        \"fs/xfs/libxfs/xfs_log_format.h\",\n                        \"fs/xfs/xfs_bmap_util.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"f0bc4d134b46607967bda1205ce3226a1bd95f42\",\n                            \"lessThan\": \"1fa2f3a7ef7ee0f2503a4b0afe24bc8c9d0820be\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f0bc4d134b46607967bda1205ce3226a1bd95f42\",\n                            \"lessThan\": \"7d3b9b2c9dc57f93f36c716ab752548cb4db9900\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f0bc4d134b46607967bda1205ce3226a1bd95f42\",\n                            \"lessThan\": \"4756c94260e69ce42612b8220c3614f02f7a11d5\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f0bc4d134b46607967bda1205ce3226a1bd95f42\",\n                            \"lessThan\": \"d84d6c1a7f1e2de9e601703a326a4c1b7b421943\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/xfs/libxfs/xfs_exchmaps.c\",\n                        \"fs/xfs/libxfs/xfs_log_format.h\",\n                        \"fs/xfs/xfs_bmap_util.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.9\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.9\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.114\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.57\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.11\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/1fa2f3a7ef7ee0f2503a4b0afe24bc8c9d0820be","https://git.kernel.org/stable/c/7d3b9b2c9dc57f93f36c716ab752548cb4db9900","https://git.kernel.org/stable/c/4756c94260e69ce42612b8220c3614f02f7a11d5","https://git.kernel.org/stable/c/d84d6c1a7f1e2de9e601703a326a4c1b7b421943"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98975","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-98975","identifiers":["CVE-2026-98975"]},"retained":false,"historicalAffected":[]}],"coverage":[]}