{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-80537", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.765Z", "datePublished": "2026-08-26T14:37:12.180Z", "dateUpdated": "2026-08-26T14:37:12.180Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-26T14:37:12.180Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfs: fix off-by-one in rtrefcount btree root level validation\n\nxfs_rtrefcountbt_compute_maxlevels() sets\n\n\tmp->m_rtrefc_maxlevels = min(d_maxlevels, r_maxlevels) + 1;\n\nwhere the trailing \"+ 1\" already accounts for the inode-root level, so the\ndeepest valid on-disk root level is m_rtrefc_maxlevels - 1 and a cursor must\nsatisfy bc_nlevels <= bc_maxlevels (= m_rtrefc_maxlevels).\n\nThe two on-disk validation paths, xfs_rtrefcountbt_verify() and\nxfs_iformat_rtrefcount(), check the root level with \">\" instead of \">=\", so a\ncrafted rtreflink (metadir + realtime + reflink) image whose\n/rtgroups/N.refcount inode has bb_level == m_rtrefc_maxlevels is accepted on\nmount. xfs_rtrefcountbt_init_cursor() then sets bc_nlevels = bb_level + 1,\nexceeding bc_maxlevels by one. Since the xfs_rtrefcountbt_cur slab object is\nsized for exactly bc_maxlevels entries, the first btree op on such a cursor\nindexes bc_levels[m_rtrefc_maxlevels] past the end of the object. This is\nreached by the first rtrefcount cursor built after mount, via log/CoW\nrecovery (xfs_reflink_recover_cow() during xfs_mountfs()) or an\nFS_IOC_GETFSMAP over the realtime device.\n\nReject a root level equal to m_rtrefc_maxlevels, matching the \">=\" form\nalready used by the sibling data-device refcount/rmap verifiers and the\nin-memory rtrmap verifier.\n\n BUG: KASAN: slab-out-of-bounds in xfs_btree_lookup (fs/xfs/libxfs/xfs_btree.c:2101)\n Write of size 2 at addr ffff888018391658 by task exploit/144\n xfs_btree_lookup (fs/xfs/libxfs/xfs_btree.c:2101)\n xfs_btree_query_range (fs/xfs/libxfs/xfs_btree.c:5308)\n xfs_refcount_recover_cow_leftovers (fs/xfs/libxfs/xfs_refcount.c:2113)\n xfs_reflink_recover_cow (fs/xfs/xfs_reflink.c:1085)\n xlog_recover_finish (fs/xfs/xfs_log_recover.c:3551)\n xfs_mountfs (fs/xfs/xfs_mount.c:1158)\n xfs_fs_fill_super (fs/xfs/xfs_super.c:1940)\n get_tree_bdev_flags (fs/super.c:1634)\n vfs_get_tree (fs/super.c:1694)\n path_mount (fs/namespace.c:4161)\n __x64_sys_mount (fs/namespace.c:4367)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n The buggy address belongs to the cache xfs_rtrefcountbt_cur of size 216\n The buggy address is located 8 bytes to the right of\n allocated 216-byte region [ffff888018391578, ffff888018391650)\n Kernel panic - not syncing: Fatal exception"}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/xfs/libxfs/xfs_rtrefcount_btree.c"], "versions": [{"version": "9abe03a0e4f978615a2b1b484b8d09ca84c16ea0", "lessThan": "8a0ecae2ecda9f9a83a496ed05c42c4b1f5c3f2d", "status": "affected", "versionType": "git"}, {"version": "9abe03a0e4f978615a2b1b484b8d09ca84c16ea0", "lessThan": "ccebfc309441e0b37b2e6ece90f18810a489d326", "status": "affected", "versionType": "git"}, {"version": "9abe03a0e4f978615a2b1b484b8d09ca84c16ea0", "lessThan": "cc3144da377de5fb422d44a2311f978623f7c900", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/xfs/libxfs/xfs_rtrefcount_btree.c"], "versions": [{"version": "6.14", "status": "affected"}, {"version": "0", "lessThan": "6.14", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.46", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.10", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "6.18.46"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "7.1.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/8a0ecae2ecda9f9a83a496ed05c42c4b1f5c3f2d"}, {"url": "https://git.kernel.org/stable/c/ccebfc309441e0b37b2e6ece90f18810a489d326"}, {"url": "https://git.kernel.org/stable/c/cc3144da377de5fb422d44a2311f978623f7c900"}], "title": "xfs: fix off-by-one in rtrefcount btree root level validation", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/xfs/libxfs/xfs_rtrefcount_btree.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "8a0ecae2ecda9f9a83a496ed05c42c4b1f5c3f2d", "status": "affected", "version": "9abe03a0e4f978615a2b1b484b8d09ca84c16ea0", "versionType": "git"}, {"lessThan": "ccebfc309441e0b37b2e6ece90f18810a489d326", "status": "affected", "version": "9abe03a0e4f978615a2b1b484b8d09ca84c16ea0", "versionType": "git"}, {"lessThan": "cc3144da377de5fb422d44a2311f978623f7c900", "status": "affected", "version": "9abe03a0e4f978615a2b1b484b8d09ca84c16ea0", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/xfs/libxfs/xfs_rtrefcount_btree.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.14"}, {"lessThan": "6.14", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.46", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.10", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfs: fix off-by-one in rtrefcount btree root level validation\n\nxfs_rtrefcountbt_compute_maxlevels() sets\n\n\tmp->m_rtrefc_maxlevels = min(d_maxlevels, r_maxlevels) + 1;\n\nwhere the trailing \"+ 1\" already accounts for the inode-root level, so the\ndeepest valid on-disk root level is m_rtrefc_maxlevels - 1 and a cursor must\nsatisfy bc_nlevels <= bc_maxlevels (= m_rtrefc_maxlevels).\n\nThe two on-disk validation paths, xfs_rtrefcountbt_verify() and\nxfs_iformat_rtrefcount(), check the root level with \">\" instead of \">=\", so a\ncrafted rtreflink (metadir + realtime + reflink) image whose\n/rtgroups/N.refcount inode has bb_level == m_rtrefc_maxlevels is accepted on\nmount. xfs_rtrefcountbt_init_cursor() then sets bc_nlevels = bb_level + 1,\nexceeding bc_maxlevels by one. Since the xfs_rtrefcountbt_cur slab object is\nsized for exactly bc_maxlevels entries, the first btree op on such a cursor\nindexes bc_levels[m_rtrefc_maxlevels] past the end of the object. This is\nreached by the first rtrefcount cursor built after mount, via log/CoW\nrecovery (xfs_reflink_recover_cow() during xfs_mountfs()) or an\nFS_IOC_GETFSMAP over the realtime device.\n\nReject a root level equal to m_rtrefc_maxlevels, matching the \">=\" form\nalready used by the sibling data-device refcount/rmap verifiers and the\nin-memory rtrmap verifier.\n\n BUG: KASAN: slab-out-of-bounds in xfs_btree_lookup (fs/xfs/libxfs/xfs_btree.c:2101)\n Write of size 2 at addr ffff888018391658 by task exploit/144\n xfs_btree_lookup (fs/xfs/libxfs/xfs_btree.c:2101)\n xfs_btree_query_range (fs/xfs/libxfs/xfs_btree.c:5308)\n xfs_refcount_recover_cow_leftovers (fs/xfs/libxfs/xfs_refcount.c:2113)\n xfs_reflink_recover_cow (fs/xfs/xfs_reflink.c:1085)\n xlog_recover_finish (fs/xfs/xfs_log_recover.c:3551)\n xfs_mountfs (fs/xfs/xfs_mount.c:1158)\n xfs_fs_fill_super (fs/xfs/xfs_super.c:1940)\n get_tree_bdev_flags (fs/super.c:1634)\n vfs_get_tree (fs/super.c:1694)\n path_mount (fs/namespace.c:4161)\n __x64_sys_mount (fs/namespace.c:4367)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n The buggy address belongs to the cache xfs_rtrefcountbt_cur of size 216\n The buggy address is located 8 bytes to the right of\n allocated 216-byte region [ffff888018391578, ffff888018391650)\n Kernel panic - not syncing: Fatal exception"}], "id": "CVE-2026-80537", "lastModified": "2026-08-26T15:17:07.890", "metrics": {}, "published": "2026-08-26T15:17:07.890", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8a0ecae2ecda9f9a83a496ed05c42c4b1f5c3f2d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/cc3144da377de5fb422d44a2311f978623f7c900"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ccebfc309441e0b37b2e6ece90f18810a489d326"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9abe03a0e4f978615a2b1b484b8d09ca84c16ea0,8a0ecae2ecda9f9a83a496ed05c42c4b1f5c3f2d)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9abe03a0e4f978615a2b1b484b8d09ca84c16ea0,ccebfc309441e0b37b2e6ece90f18810a489d326)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9abe03a0e4f978615a2b1b484b8d09ca84c16ea0,cc3144da377de5fb422d44a2311f978623f7c900)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "6.14"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.14)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.46,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.10,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-08-26T15:45:04.430231+00:00", "updated": "2026-08-26T18:45:10.060964+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-193", "CWE-119"]}