{ "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" } } } }