{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72369","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-09T03:40:39.922Z","datePublished":"2026-08-15T05:56:05.995Z","dateUpdated":"2026-08-17T05:43:23.188Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-17T05:43:23.188Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nminix: avoid overflow in bitmap block count calculation\n\nminix_check_superblock() uses minix_blocks_needed() to verify that the\non-disk imap and zmap block counts are large enough for the advertised\ninode and zone counts.\n\nThe helper currently performs DIV_ROUND_UP() in unsigned int arithmetic.\nA Minix v3 image can set s_ninodes or s_zones near UINT_MAX so the\naddition inside DIV_ROUND_UP() wraps to zero. That makes a zero imap/zmap\nblock count look valid, after which minix_fill_super() can dereference\ns_imap[0] or s_zmap[0] even though no bitmap buffers were allocated.\n\nImpact: mounting a crafted Minix v3 image whose s_ninodes or s_zones is\nnear UINT_MAX makes minix_check_superblock() accept a zero bitmap-block\ncount and minix_fill_super() dereference s_imap[0]/s_zmap[0], panicking\nthe kernel.\n\nThe divisor is the bitmap capacity in bits, blocksize * 8, which is\nalways a power of two: minix_fill_super() obtains the block size through\nsb_set_blocksize(), and blk_validate_block_size() rejects any size that\nis not a power of two. Use DIV_ROUND_UP_POW2(), which divides before\nadding the round-up term and so cannot overflow for a power-of-two\ndivisor."}],"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 only when the kernel parses a crafted Minix V3 on-disk superblock during block-device mount (mount(2)/fsopen+fsmount → get_tree_bdev → minix_fill_super); Minix is not exposed via ksmbd, nfsd, or any network protocol handler.\nAC:L - A Minix V3 image with s_ninodes or s_zones near UINT_MAX and zero/small imap/zmap block counts deterministically makes minix_blocks_needed() wrap to zero, bypassing minix_check_superblock() every time without races or attacker-uncontrollable heap layout.\nPR:L - may_mount() requires CAP_SYS_ADMIN in the mount namespace, which unprivileged attackers obtain inside user namespaces; syzbot reproduced this via fuzzed mounts, and a loop-backed image supplies the required block device without init-namespace root.\nUI:N - No victim action is needed when the attacker with mount capability (e.g., CAP_SYS_ADMIN in a user/mount namespace) mounts their own malicious Minix v3 loop image; exploitation does not depend on tricking another user to open a file or insert removable media.\nS:U - The flaw corrupts or crashes kernel memory during superblock initialization in the mounting context only; it does not cross VM, container, or IOMMU boundaries and matches standard in-kernel memory-corruption/DoS impact (Scope Unchanged).\nC:H - With imap_blocks=1 and overflow-bypassed zmap_blocks=0, s_zmap=&map[1] performs an out-of-bounds heap read of a buffer_head pointer past the under-allocated map; s_imap[0]/s_zmap[0] dereferences on zero-block images also read uninitialized/garbage pointers before panic.\nI:H - After the overflow bypass, minix_set_bit(0,sbi->s_zmap[0]->b_data) uses the OOB-read pointer and can set a bit at an attacker-influenced kernel address; this is exploitable memory corruption during mount, not a guaranteed-safe NULL-only crash.\nA:H - minix_fill_super() dereferences unallocated s_imap[0]/s_zmap[0] entries and faults the kernel (oops/panic); even the one-bit write via corrupted pointers can immediately fault, causing total loss of kernel availability on the affected system."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/minix/minix.h"],"versions":[{"version":"2bb588cede1c1969e49c0a2822c8cb8b346b7682","lessThan":"a11ebaab50d27d6c4c78506f84ff36452e0b901d","status":"affected","versionType":"git"},{"version":"f57ccd4657c7f082dc47e5b9e18a883bb5f9118f","lessThan":"959c95340a9e19cd333b4c18935fdeecbb2f319d","status":"affected","versionType":"git"},{"version":"31fefc18096cdc5549cfa54964d90e0b3229aedc","lessThan":"abe3536a4bedcc43de80b6d4d7e3d57e9ba382a5","status":"affected","versionType":"git"},{"version":"8c97a6ddc95690a938ded44b4e3202f03f15078c","lessThan":"8a29e60e2176b02e04f8737c8b32b696230eb0c5","status":"affected","versionType":"git"},{"version":"8c97a6ddc95690a938ded44b4e3202f03f15078c","lessThan":"fb3e566cafc38fe3ba35e6843a2d529a3748870c","status":"affected","versionType":"git"},{"version":"a051ecf5c5b0387840dc210413ed3bc7fbdaa69c","status":"affected","versionType":"git"},{"version":"d791c544efd6b9c944b43cf7f502e5bcb02fb941","status":"affected","versionType":"git"},{"version":"66c7c239c65341f99ae388d4d53dc9df2bcb9925","status":"affected","versionType":"git"},{"version":"1efc128ee4adbc23e082715425ff895449d233bc","status":"affected","versionType":"git"},{"version":"6.6.128","lessThan":"6.6.145","status":"affected","versionType":"semver"},{"version":"6.12.75","lessThan":"6.12.97","status":"affected","versionType":"semver"},{"version":"6.18.16","lessThan":"6.18.40","status":"affected","versionType":"semver"},{"version":"5.10.252","lessThan":"5.11","status":"affected","versionType":"semver"},{"version":"5.15.202","lessThan":"5.16","status":"affected","versionType":"semver"},{"version":"6.1.165","lessThan":"6.2","status":"affected","versionType":"semver"},{"version":"6.19.6","lessThan":"6.20","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/minix/minix.h"],"versions":[{"version":"7.0","status":"affected"},{"version":"0","lessThan":"7.0","status":"unaffected","versionType":"semver"},{"version":"6.6.145","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.97","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.40","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.5","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":"6.6.128","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.75","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18.16","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.252"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.202"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.165"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19.6"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/a11ebaab50d27d6c4c78506f84ff36452e0b901d"},{"url":"https://git.kernel.org/stable/c/959c95340a9e19cd333b4c18935fdeecbb2f319d"},{"url":"https://git.kernel.org/stable/c/abe3536a4bedcc43de80b6d4d7e3d57e9ba382a5"},{"url":"https://git.kernel.org/stable/c/8a29e60e2176b02e04f8737c8b32b696230eb0c5"},{"url":"https://git.kernel.org/stable/c/fb3e566cafc38fe3ba35e6843a2d529a3748870c"}],"title":"minix: avoid overflow in bitmap block count calculation","x_generator":{"engine":"bippy-1.2.0"}}}}