{"id":"CVE-2026-89574","state":"PUBLISHED","title":"dm array: validate array block headers on read","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm array: validate array block headers on read\n\narray_block_check() validates blocknr and csum and nothing else, while\nnode_check(), next to it, has bounded the structural fields since both\nwere written. dm_array_cursor_next() takes its loop bound from the\non-disk nr_entries and element_at() is unguarded pointer arithmetic, so\na count larger than the block holds keeps the cursor in one block while\nthe index grows past it and the read walks off the dm-bufio buffer --\ndm_cache_load_mappings() drives it once per cache block at activation.\n\nCheck the header against itself: reject a zero value_size, require\nmax_entries to equal calc_max_entries() for that value_size and block\nsize, and require nr_entries to fit. Equality rather than an upper bound,\nsince a count below the real capacity trips BUG_ON() in fill_ablock() and\ntrim_ablock(). Metadata dm-array writes satisfies all three.","publishedAt":"2026-09-11T19:44:42.494Z","updatedAt":"2026-10-30T12:32:15.267Z","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":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","status":"affected","lessThan":"e09d8b34ed199c8b7d7528c2b8324aa7cff712f8","versionType":"git"},{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","status":"affected","lessThan":"0e3b8f371c385c212b6e6f76c66f5b3f5bcfea62","versionType":"git"},{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","status":"affected","lessThan":"67adda7ed5da3e3b64f5b9021a02c21fb374fd9c","versionType":"git"},{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","status":"affected","lessThan":"b33f76d33aaeacf3baf3370d8d64985169b36600","versionType":"git"},{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","status":"affected","lessThan":"9808ddffb4bc659352df3020cd84d9d864820ee5","versionType":"git"},{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","status":"affected","lessThan":"2965787723084835b18dfe993cd450ebf5bd4540","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/persistent-data/dm-array.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.9","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.109","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.50","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/persistent-data/dm-array.c"]}],"references":["https://git.kernel.org/stable/c/e09d8b34ed199c8b7d7528c2b8324aa7cff712f8","https://git.kernel.org/stable/c/0e3b8f371c385c212b6e6f76c66f5b3f5bcfea62","https://git.kernel.org/stable/c/67adda7ed5da3e3b64f5b9021a02c21fb374fd9c","https://git.kernel.org/stable/c/b33f76d33aaeacf3baf3370d8d64985169b36600","https://git.kernel.org/stable/c/9808ddffb4bc659352df3020cd84d9d864820ee5","https://git.kernel.org/stable/c/2965787723084835b18dfe993cd450ebf5bd4540"],"weaknesses":[],"ingestedAt":"2026-10-30T12:50:04.827Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/89xxx/CVE-2026-89574.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89574","state":"PUBLISHED","datePublished":"2026-09-11T19:44:42.494Z","dateUpdated":"2026-10-30T12:32:15.267Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.727Z"},"containers":{"cna":{"title":"dm array: validate array block headers on read","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm array: validate array block headers on read\n\narray_block_check() validates blocknr and csum and nothing else, while\nnode_check(), next to it, has bounded the structural fields since both\nwere written. dm_array_cursor_next() takes its loop bound from the\non-disk nr_entries and element_at() is unguarded pointer arithmetic, so\na count larger than the block holds keeps the cursor in one block while\nthe index grows past it and the read walks off the dm-bufio buffer --\ndm_cache_load_mappings() drives it once per cache block at activation.\n\nCheck the header against itself: reject a zero value_size, require\nmax_entries to equal calc_max_entries() for that value_size and block\nsize, and require nr_entries to fit. Equality rather than an upper bound,\nsince a count below the real capacity trips BUG_ON() in fill_ablock() and\ntrim_ablock(). Metadata dm-array writes satisfies all three."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","status":"affected","lessThan":"e09d8b34ed199c8b7d7528c2b8324aa7cff712f8","versionType":"git"},{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","status":"affected","lessThan":"0e3b8f371c385c212b6e6f76c66f5b3f5bcfea62","versionType":"git"},{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","status":"affected","lessThan":"67adda7ed5da3e3b64f5b9021a02c21fb374fd9c","versionType":"git"},{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","status":"affected","lessThan":"b33f76d33aaeacf3baf3370d8d64985169b36600","versionType":"git"},{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","status":"affected","lessThan":"9808ddffb4bc659352df3020cd84d9d864820ee5","versionType":"git"},{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","status":"affected","lessThan":"2965787723084835b18dfe993cd450ebf5bd4540","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/persistent-data/dm-array.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.9","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.109","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.50","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/persistent-data/dm-array.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/e09d8b34ed199c8b7d7528c2b8324aa7cff712f8"},{"url":"https://git.kernel.org/stable/c/0e3b8f371c385c212b6e6f76c66f5b3f5bcfea62"},{"url":"https://git.kernel.org/stable/c/67adda7ed5da3e3b64f5b9021a02c21fb374fd9c"},{"url":"https://git.kernel.org/stable/c/b33f76d33aaeacf3baf3370d8d64985169b36600"},{"url":"https://git.kernel.org/stable/c/9808ddffb4bc659352df3020cd84d9d864820ee5"},{"url":"https://git.kernel.org/stable/c/2965787723084835b18dfe993cd450ebf5bd4540"}],"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 - The bug is reached when the kernel reads attacker-crafted dm-array metadata from a local block device during device-mapper activation (dm-cache dm_cache_load_mappings, dm-clone bitset load, or dm-era array resize), not via a network protocol.\nAC:L - The attacker fully controls the on-disk array-block header (nr_entries, max_entries, value_size) and can compute a matching checksum, so activation deterministically walks off the dm-bufio buffer; there is no race or attacker-uncontrollable memory layout.\nPR:L - Device-mapper ioctls require init-namespace CAP_SYS_ADMIN and are not reachable via user namespaces, but the malformed data is on-disk metadata, so the attacker only needs write access to the backing store (loop file, VM/container disk, iSCSI/NBD LUN) that a dm-cache/dm-era/dm-clone stack is built on.\nUI:N - Once corrupt metadata is on the backing store, LVM/udev autoactivation, boot, or reattachment of the volume loads mappings without a separate victim action such as mounting a filesystem or opening a file.\nS:U - The out-of-bounds access is confined to kernel dm-bufio metadata buffers on the same host; this is ordinary kernel memory corruption, not a VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:H - dm_array_cursor_next() takes its loop bound from on-disk nr_entries while element_at() is unguarded pointer arithmetic, so a too-large count keeps the cursor in one block and reads past the dm-bufio data buffer (typically a 4K slab/page) for every cache block at activation, an unbounded kernel out-of-bounds read.\nI:H - Unchecked headers let fill_ablock()/trim_ablock() hit BUG_ON on resize, and out-of-bounds mapping, hint, and bitset values from adjacent kernel memory are installed into the cache policy and then used for origin/cache I/O, giving a memory-corruption integrity primitive.\nA:H - Walking off the dm-bufio buffer causes a kernel oops or KASAN panic, and an undersized on-disk max_entries hits BUG_ON in fill_ablock() and trim_ablock() during array resize at activation."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:32:15.267Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.9","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.9","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.9","versionEndExcluding":"6.12.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.9","versionEndExcluding":"6.18.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.9","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.9","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-89574","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T19:24:26.489606Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T19:26:44.762Z"}}]}}}