{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-38218", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:23.995Z", "datePublished": "2025-07-04T13:37:35.157Z", "dateUpdated": "2026-08-05T12:00:26.742Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:00:26.742Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to do sanity check on sit_bitmap_size\n\nw/ below testcase, resize will generate a corrupted image which\ncontains inconsistent metadata, so when mounting such image, it\nwill trigger kernel panic:\n\ntouch img\ntruncate -s $((512*1024*1024*1024)) img\nmkfs.f2fs -f img $((256*1024*1024))\nresize.f2fs -s -i img -t $((1024*1024*1024))\nmount img /mnt/f2fs\n\n------------[ cut here ]------------\nkernel BUG at fs/f2fs/segment.h:863!\nOops: invalid opcode: 0000 [#1] SMP PTI\nCPU: 11 UID: 0 PID: 3922 Comm: mount Not tainted 6.15.0-rc1+ #191 PREEMPT(voluntary)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nRIP: 0010:f2fs_ra_meta_pages+0x47c/0x490\n\nCall Trace:\n f2fs_build_segment_manager+0x11c3/0x2600\n f2fs_fill_super+0xe97/0x2840\n mount_bdev+0xf4/0x140\n legacy_get_tree+0x2b/0x50\n vfs_get_tree+0x29/0xd0\n path_mount+0x487/0xaf0\n __x64_sys_mount+0x116/0x150\n do_syscall_64+0x82/0x190\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\nRIP: 0033:0x7fdbfde1bcfe\n\nThe reaseon is:\n\nsit_i->bitmap_size is 192, so size of sit bitmap is 192*8=1536, at maximum\nthere are 1536 sit blocks, however MAIN_SEGS is 261893, so that sit_blk_cnt\nis 4762, build_sit_entries() -> current_sit_addr() tries to access\nout-of-boundary in sit_bitmap at offset from [1536, 4762), once sit_bitmap\nand sit_bitmap_mirror is not the same, it will trigger f2fs_bug_on().\n\nLet's add sanity check in f2fs_sanity_check_ckpt() to avoid panic." } ], "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 vulnerability is reached through the local `mount(2)` path (`f2fs_fill_super` → `f2fs_build_segment_manager` → `build_sit_entries`) when a crafted f2fs image is attached, and the subsequent OOB write is reached via ordinary local file writes triggering a checkpoint. No network exposure exists.\nAC:L - The attacker fully controls the on-disk `sit_ver_bitmap_bytesize` and `segment_count_main` fields, so the out-of-bounds offset is deterministic and reproducible on every mount — the PoC is four shell commands with no race, timing, or memory-layout luck required to trigger it.\nPR:L - An unprivileged local user can get the crafted image mounted through removable-media auto-mount paths that are ubiquitous for f2fs — Android vold mounting SD/adoptable storage and udisks2 on desktops — without holding real `CAP_SYS_ADMIN` in the init namespace.\nUI:N - The attacker supplies and mounts the image themselves via auto-mount or delegated mount rights; no action by a separate victim user is needed, and the follow-on OOB write in `f2fs_flush_sit_entries()` fires from the attacker's own writes.\nS:U - The out-of-bounds access corrupts kernel slab memory within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - `current_sit_addr()` performs a heap out-of-bounds read of the `kmemdup`'d `sit_bitmap` at an attacker-chosen offset extending thousands of bits (up to ~19 KB) past the slab object, and the values read steer computed metadata block addresses, providing an oracle over adjacent kernel heap contents.\nI:H - `f2fs_flush_sit_entries()` → `get_next_sit_folio()` → `set_to_next_sit()` → `f2fs_change_bit()` performs an out-of-bounds bit flip at the same attacker-chosen offset, corrupting adjacent slab objects — a heap-corruption primitive suitable for control-flow hijacking with standard grooming.\nA:H - The reported impact is an immediate kernel panic — `BUG()` via `f2fs_bug_on()` at `fs/f2fs/segment.h:863` inside `f2fs_ra_meta_pages()` during mount — and the far out-of-bounds accesses can also fault on unmapped memory." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/f2fs/super.c" ], "versions": [ { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "82f51bff393e4c12cf4de553120ca831cfa4ef19", "status": "affected", "versionType": "git" }, { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "38ef48a8afef8df646b6f6ae7abb872f18b533c1", "status": "affected", "versionType": "git" }, { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "ad862f71016ba38039df1c96ed55c0a4314cc183", "status": "affected", "versionType": "git" }, { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "79ef8a6c4ec53d327580fd7d2b522cf4f1d05b0c", "status": "affected", "versionType": "git" }, { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "ee1b421c469876544e297ec1090574bd76100247", "status": "affected", "versionType": "git" }, { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "3e5ac62a56a24f4d88ce8ffd7bc452428b235868", "status": "affected", "versionType": "git" }, { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "5db0d252c64e91ba1929c70112352e85dc5751e7", "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/super.c" ], "versions": [ { "version": "3.8", "status": "affected" }, { "version": "0", "lessThan": "3.8", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.239", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.186", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.142", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.95", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.35", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.15.4", "lessThanOrEqual": "6.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.16", "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": "3.8", "versionEndExcluding": "5.10.239" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "5.15.186" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.1.142" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.6.95" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.12.35" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.15.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.16" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/82f51bff393e4c12cf4de553120ca831cfa4ef19" }, { "url": "https://git.kernel.org/stable/c/38ef48a8afef8df646b6f6ae7abb872f18b533c1" }, { "url": "https://git.kernel.org/stable/c/ad862f71016ba38039df1c96ed55c0a4314cc183" }, { "url": "https://git.kernel.org/stable/c/79ef8a6c4ec53d327580fd7d2b522cf4f1d05b0c" }, { "url": "https://git.kernel.org/stable/c/ee1b421c469876544e297ec1090574bd76100247" }, { "url": "https://git.kernel.org/stable/c/3e5ac62a56a24f4d88ce8ffd7bc452428b235868" }, { "url": "https://git.kernel.org/stable/c/5db0d252c64e91ba1929c70112352e85dc5751e7" } ], "title": "f2fs: fix to do sanity check on sit_bitmap_size", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T17:35:36.324Z" } } ] } }