{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40167", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.176Z", "datePublished": "2025-11-12T10:26:24.498Z", "dateUpdated": "2026-08-05T12:08:12.384Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:08:12.384Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: detect invalid INLINE_DATA + EXTENTS flag combination\n\nsyzbot reported a BUG_ON in ext4_es_cache_extent() when opening a verity\nfile on a corrupted ext4 filesystem mounted without a journal.\n\nThe issue is that the filesystem has an inode with both the INLINE_DATA\nand EXTENTS flags set:\n\n EXT4-fs error (device loop0): ext4_cache_extents:545: inode #15:\n comm syz.0.17: corrupted extent tree: lblk 0 < prev 66\n\nInvestigation revealed that the inode has both flags set:\n DEBUG: inode 15 - flag=1, i_inline_off=164, has_inline=1, extents_flag=1\n\nThis is an invalid combination since an inode should have either:\n- INLINE_DATA: data stored directly in the inode\n- EXTENTS: data stored in extent-mapped blocks\n\nHaving both flags causes ext4_has_inline_data() to return true, skipping\nextent tree validation in __ext4_iget(). The unvalidated out-of-order\nextents then trigger a BUG_ON in ext4_es_cache_extent() due to integer\nunderflow when calculating hole sizes.\n\nFix this by detecting this invalid flag combination early in ext4_iget()\nand rejecting the corrupted inode." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The invalid flag combination can only be delivered on a crafted ext4 on-disk image attached locally (USB stick, SD card, loop-mounted file), and the bug fires during `ext4_iget()`/`ext4_map_blocks()` on the local mount; there is no network-facing input into this code path.\nAC:L - The attacker fully controls the image and merely sets both INLINE_DATA_FL and EXTENTS_FL on an inode with a `system.data` xattr, formatting without a journal — this deterministically bypasses `ext4_ext_check_inode()` and trips `BUG_ON(end < lblk)` on every open, with no race, timing, or memory-layout condition outside the attacker's control.\nPR:N - The attacker needs no account or privilege on the target — they only supply the malicious filesystem image, and the privileged mount plus the subsequent file access are performed by the victim, an indexer/thumbnailer, or an automounter such as udisks2 or vold.\nUI:R - Because `ext4_fs_type` lacks `FS_USERNS_MOUNT` and `INLINE_DATA_FL` is not in `EXT4_FL_USER_MODIFIABLE`, the corrupt inode cannot be created on a live filesystem; a user or automounter must actually mount the attacker-supplied ext4 image.\nS:U - The out-of-bounds accesses and the panic are confined to the mounting host's kernel memory and its own filesystem, within a single security authority; no VM, hypervisor, IOMMU, or sandbox boundary is crossed.\nC:H - Skipping `__ext4_ext_check()` leaves `eh_entries` unvalidated (up to 65535 versus the 4 that fit in the 60-byte `i_block[]`), so `ext4_cache_extents()` and `ext4_ext_binsearch()` read hundreds of kilobytes past the `ext4_inode_info` slab object, and those out-of-bounds kernel bytes are interpreted as physical block numbers that drive real disk reads and are reported back to userspace through FIEMAP.\nI:H - The unvalidated `eh_max` defeats the `eh_entries >= eh_max` guard in `ext4_ext_insert_extent()`, so extent entries are memmoved and written past the end of `i_block[]` into adjacent `ext4_inode_info` slab fields, giving a heap out-of-bounds write; the missing `ext4_valid_extent()`/`ext4_inode_block_valid()` check additionally lets writes and block frees land on superblock, bitmap, and group-descriptor blocks.\nA:H - The out-of-order extents produce an integer underflow in `lblk - prev` and hit `BUG_ON(end < lblk)` in `ext4_es_cache_extent()`, an immediate and reliably reproducible kernel panic on every access to the crafted file; the out-of-bounds slab reads independently oops the kernel on KASAN and hardened builds." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/ext4/inode.c" ], "versions": [ { "version": "f19d5870cbf72d4cb2a8e1f749dff97af99b071e", "lessThan": "4954d297c91d292630ab43ba4d195dc371ce65d3", "status": "affected", "versionType": "git" }, { "version": "f19d5870cbf72d4cb2a8e1f749dff97af99b071e", "lessThan": "f061f7c331fc16250fc82aa68964f35821687217", "status": "affected", "versionType": "git" }, { "version": "f19d5870cbf72d4cb2a8e1f749dff97af99b071e", "lessThan": "2e9e10657b04152ed0d6ecae8d0c02a3405e28f5", "status": "affected", "versionType": "git" }, { "version": "f19d5870cbf72d4cb2a8e1f749dff97af99b071e", "lessThan": "1437c95ab2a28b138d4521653583729f61ccb48b", "status": "affected", "versionType": "git" }, { "version": "f19d5870cbf72d4cb2a8e1f749dff97af99b071e", "lessThan": "cb6039b68efa547b676a8a10fc4618d9d1865c23", "status": "affected", "versionType": "git" }, { "version": "f19d5870cbf72d4cb2a8e1f749dff97af99b071e", "lessThan": "de985264eef64be8a90595908f2e6a87946dad34", "status": "affected", "versionType": "git" }, { "version": "f19d5870cbf72d4cb2a8e1f749dff97af99b071e", "lessThan": "1f5ccd22ff482639133f2a0fe08f6d19d0e68717", "status": "affected", "versionType": "git" }, { "version": "f19d5870cbf72d4cb2a8e1f749dff97af99b071e", "lessThan": "1d3ad183943b38eec2acf72a0ae98e635dc8456b", "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/ext4/inode.c" ], "versions": [ { "version": "3.8", "status": "affected" }, { "version": "0", "lessThan": "3.8", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.301", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.246", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.196", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.158", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.114", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.55", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.5", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "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": "5.4.301" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "5.10.246" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "5.15.196" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.1.158" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.6.114" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.12.55" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.17.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/4954d297c91d292630ab43ba4d195dc371ce65d3" }, { "url": "https://git.kernel.org/stable/c/f061f7c331fc16250fc82aa68964f35821687217" }, { "url": "https://git.kernel.org/stable/c/2e9e10657b04152ed0d6ecae8d0c02a3405e28f5" }, { "url": "https://git.kernel.org/stable/c/1437c95ab2a28b138d4521653583729f61ccb48b" }, { "url": "https://git.kernel.org/stable/c/cb6039b68efa547b676a8a10fc4618d9d1865c23" }, { "url": "https://git.kernel.org/stable/c/de985264eef64be8a90595908f2e6a87946dad34" }, { "url": "https://git.kernel.org/stable/c/1f5ccd22ff482639133f2a0fe08f6d19d0e68717" }, { "url": "https://git.kernel.org/stable/c/1d3ad183943b38eec2acf72a0ae98e635dc8456b" } ], "title": "ext4: detect invalid INLINE_DATA + EXTENTS flag combination", "x_generator": { "engine": "bippy-1.2.0" } } } }