{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89840", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.769Z", "datePublished": "2026-09-16T10:31:14.646Z", "dateUpdated": "2026-10-21T12:49:02.980Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:49:02.980Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: validate MOVE_RANGE destination size\n\nF2FS_IOC_MOVE_RANGE checks the source range, but not the destination end\nbefore updating i_size. A source hole can expose this: __clone_blkaddrs()\nskips NULL_ADDR entries and returns success, so the caller can still extend\nthe destination inode with unchecked pos_out + len.\n\nReject destination overflow and use inode_newsize_ok() before extending\nthe destination inode." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H", "baseScore": 7.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - F2FS_IOC_MOVE_RANGE is a local ioctl (f2fs_ioctl → f2fs_ioc_move_range → f2fs_move_file_range) on f2fs file descriptors. f2fs has no remap_file_range, so nfsd/ksmbd copy_file_range cannot reach this path.\nAC:L - The attacker fully controls pos_out and len and can ftruncate a sparse source so __clone_blkaddrs skips NULL_ADDR holes and returns success, making the unchecked destination i_size update deterministic with no race or uncontrollable layout.\nPR:L - f2fs_ioc_move_range has no capable() check; it only needs FMODE_READ|FMODE_WRITE on the source and FMODE_WRITE on the destination. Any unprivileged user with files on mounted f2fs (Android /data, embedded userdata) can trigger it.\nUI:N - The attacker opens their own files on an already-mounted f2fs volume and issues F2FS_IOC_MOVE_RANGE; no separate victim action such as mounting a filesystem or opening a crafted file is required.\nS:U - Impact is corruption of f2fs inode size metadata and subsequent filesystem/kernel state on the local host, a standard kernel compromise within the same security authority with no VM escape or IOMMU bypass.\nC:N - The bug writes an oversized or overflowed i_size; reads of the resulting sparse file return zeros or EOF (negative i_size makes pos >= i_size), and lookups beyond max_file_blocks fail with -E2BIG, so there is no kernel-memory or cross-file disclosure primitive.\nI:H - Missing overflow and inode_newsize_ok() checks let the attacker set destination i_size past s_maxbytes or wrap size_t into a negative loff_t, persisting corrupt on-disk inode size and poisoning later paths (fallocate COLLAPSE nrpages, __exchange_data_block ALLOC_NODE) that trust i_size for block-tree updates.\nA:H - A poisoned i_size enables unbounded node-tree walks and block-exchange loops (SEEK_DATA/HOLE, fallocate COLLAPSE via DIV_ROUND_UP(i_size)), can hang the kernel or exhaust node space, and leaves durable filesystem corruption on shared f2fs userdata." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/f2fs/file.c" ], "versions": [ { "version": "4dd6f977fc778e5a0da604e5f8cb2f36d163d27b", "lessThan": "54c587f3f95ce2d6932a16566db83f73cc4313e1", "status": "affected", "versionType": "git" }, { "version": "4dd6f977fc778e5a0da604e5f8cb2f36d163d27b", "lessThan": "bca61ee5192ea47003722486ae9588a2a4bb47b6", "status": "affected", "versionType": "git" }, { "version": "4dd6f977fc778e5a0da604e5f8cb2f36d163d27b", "lessThan": "db13064669526494cd78ba3a4394063b740e940c", "status": "affected", "versionType": "git" }, { "version": "4dd6f977fc778e5a0da604e5f8cb2f36d163d27b", "lessThan": "dcae1eeda53149f219dd6af93b3083b7271c1c63", "status": "affected", "versionType": "git" }, { "version": "4dd6f977fc778e5a0da604e5f8cb2f36d163d27b", "lessThan": "e533889fc26aea0cd83c90327063f272061dd820", "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/f2fs/file.c" ], "versions": [ { "version": "4.8", "status": "affected" }, { "version": "0", "lessThan": "4.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.112", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.53", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.5", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "4.8", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.12.112" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.18.53" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "7.2.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/54c587f3f95ce2d6932a16566db83f73cc4313e1" }, { "url": "https://git.kernel.org/stable/c/bca61ee5192ea47003722486ae9588a2a4bb47b6" }, { "url": "https://git.kernel.org/stable/c/db13064669526494cd78ba3a4394063b740e940c" }, { "url": "https://git.kernel.org/stable/c/dcae1eeda53149f219dd6af93b3083b7271c1c63" }, { "url": "https://git.kernel.org/stable/c/e533889fc26aea0cd83c90327063f272061dd820" } ], "title": "f2fs: validate MOVE_RANGE destination size", "x_generator": { "engine": "bippy-1.2.0" } } } }