{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89829", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.769Z", "datePublished": "2026-09-16T10:31:01.761Z", "dateUpdated": "2026-10-19T08:53:22.927Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:53:22.927Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to pass folio->index to f2fs_sanity_check_node_footer()\n\nOtherwise in f2fs_sanity_check_node_footer(), it will check the\nsame nid incorrectly." } ], "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 defect is in f2fs __write_node_folio() on the node-mapping writeback path, reached only from local VFS operations (fsync, write, checkpoint, GC, or reclaim) on a mounted f2fs volume; no network protocol (ksmbd/nfsd/packet) processes this node-footer check.\nAC:L - A crafted f2fs image fully controls the on-disk node footer nid. Related syzbot reports show that async node readahead of a fuzzed image followed by writeback deterministically hits the mismatched-nid case, with no race or layout the attacker cannot arrange.\nPR:L - Mounting f2fs requires privilege (no FS_USERNS_MOUNT), but once the volume is mounted—Android userdata, automounted SD/USB, or a shared workstation—any unprivileged local user can dirty node pages via write/fsync/fallocate/truncate and enter __write_node_folio with no capability check.\nUI:N - After the crafted image is mounted, the attacker triggers node writeback themselves through ordinary file syscalls or in-kernel checkpoint/reclaim; no separate victim action such as opening a file or confirming a prompt is required.\nS:U - The impact is kernel memory and f2fs metadata corruption on the host that mounted the volume; it does not cross a VM, IOMMU, or guest-to-host security boundary.\nC:H - __write_node_folio uses the attacker-controlled footer nid as the NAT key without a range check, so current_nat_addr() indexes nat_bitmap at an attacker-chosen offset (nid/NAT_ENTRY_PER_BLOCK), an unbounded out-of-bounds kernel read. The same nid confusion later parses the planted node with the wrong layout, leaking adjacent folio contents as in CVE-2025-40025.\nI:H - set_node_addr() and f2fs_do_write_node_page() commit the node folio under the footer nid, overwriting an arbitrary NAT entry and remapping any node. Subsequent operations on that nid write through the wrong inode-vs-dnode layout, producing out-of-bounds metadata writes past the node folio.\nA:H - A mismatched nid that fails f2fs_get_node_info() takes redirty_out, looping writepages indefinitely (the hang this check was added to stop). A nid that proceeds hits f2fs_bug_on() in set_node_addr()/write_end_io, panicking with CONFIG_F2FS_CHECK_FS or WARNing and corrupting the filesystem otherwise." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/f2fs/node.c" ], "versions": [ { "version": "cd2fec912a0f04390d446ed692f73f2da842855f", "lessThan": "a984446aa9d5b787afa3023fc7b44017b80fe3bc", "status": "affected", "versionType": "git" }, { "version": "0a736109c9d29de0c26567e42cb99b27861aa8ba", "lessThan": "0b196c07407f48a41cd9741cf53e10cb1e23d2e5", "status": "affected", "versionType": "git" }, { "version": "0a736109c9d29de0c26567e42cb99b27861aa8ba", "lessThan": "7e188e9f9437ab47c3237d609f1b26348d6fea1a", "status": "affected", "versionType": "git" }, { "version": "971aa8e2a4043d92bf62061b79f74fd4ac59165a", "status": "affected", "versionType": "git" }, { "version": "6.18.13", "lessThan": "6.18.51", "status": "affected", "versionType": "semver" }, { "version": "6.19.3", "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/f2fs/node.c" ], "versions": [ { "version": "7.0", "status": "affected" }, { "version": "0", "lessThan": "7.0", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.51", "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": "6.18.13", "versionEndExcluding": "6.18.51" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0", "versionEndExcluding": "7.2.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0", "versionEndExcluding": "7.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/a984446aa9d5b787afa3023fc7b44017b80fe3bc" }, { "url": "https://git.kernel.org/stable/c/0b196c07407f48a41cd9741cf53e10cb1e23d2e5" }, { "url": "https://git.kernel.org/stable/c/7e188e9f9437ab47c3237d609f1b26348d6fea1a" } ], "title": "f2fs: fix to pass folio->index to f2fs_sanity_check_node_footer()", "x_generator": { "engine": "bippy-1.2.0" } } } }