{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89574","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.727Z","datePublished":"2026-09-11T19:44:42.494Z","dateUpdated":"2026-09-13T06:31:11.485Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-13T06:31:11.485Z"},"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."}],"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."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/persistent-data/dm-array.c"],"versions":[{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","lessThan":"67adda7ed5da3e3b64f5b9021a02c21fb374fd9c","status":"affected","versionType":"git"},{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","lessThan":"b33f76d33aaeacf3baf3370d8d64985169b36600","status":"affected","versionType":"git"},{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","lessThan":"9808ddffb4bc659352df3020cd84d9d864820ee5","status":"affected","versionType":"git"},{"version":"6513c29f44f2cc970c0e9fecfe5a6526c3e73025","lessThan":"2965787723084835b18dfe993cd450ebf5bd4540","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/persistent-data/dm-array.c"],"versions":[{"version":"3.9","status":"affected"},{"version":"0","lessThan":"3.9","status":"unaffected","versionType":"semver"},{"version":"6.12.109","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.50","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.4","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","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":"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-rc1"}]}]}],"references":[{"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"}],"title":"dm array: validate array block headers on read","x_generator":{"engine":"bippy-1.2.0"}}}}