{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40295", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.185Z", "datePublished": "2025-12-08T00:46:18.950Z", "dateUpdated": "2026-05-11T21:46:35.245Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T21:46:35.245Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfscrypt: fix left shift underflow when inode->i_blkbits > PAGE_SHIFT\n\nWhen simulating an nvme device on qemu with both logical_block_size and\nphysical_block_size set to 8 KiB, an error trace appears during\npartition table reading at boot time. The issue is caused by\ninode->i_blkbits being larger than PAGE_SHIFT, which leads to a left\nshift of -1 and triggering a UBSAN warning.\n\n[ 2.697306] ------------[ cut here ]------------\n[ 2.697309] UBSAN: shift-out-of-bounds in fs/crypto/inline_crypt.c:336:37\n[ 2.697311] shift exponent -1 is negative\n[ 2.697315] CPU: 3 UID: 0 PID: 274 Comm: (udev-worker) Not tainted 6.18.0-rc2+ #34 PREEMPT(voluntary)\n[ 2.697317] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\n[ 2.697320] Call Trace:\n[ 2.697324] \n[ 2.697325] dump_stack_lvl+0x76/0xa0\n[ 2.697340] dump_stack+0x10/0x20\n[ 2.697342] __ubsan_handle_shift_out_of_bounds+0x1e3/0x390\n[ 2.697351] bh_get_inode_and_lblk_num.cold+0x12/0x94\n[ 2.697359] fscrypt_set_bio_crypt_ctx_bh+0x44/0x90\n[ 2.697365] submit_bh_wbc+0xb6/0x190\n[ 2.697370] block_read_full_folio+0x194/0x270\n[ 2.697371] ? __pfx_blkdev_get_block+0x10/0x10\n[ 2.697375] ? __pfx_blkdev_read_folio+0x10/0x10\n[ 2.697377] blkdev_read_folio+0x18/0x30\n[ 2.697379] filemap_read_folio+0x40/0xe0\n[ 2.697382] filemap_get_pages+0x5ef/0x7a0\n[ 2.697385] ? mmap_region+0x63/0xd0\n[ 2.697389] filemap_read+0x11d/0x520\n[ 2.697392] blkdev_read_iter+0x7c/0x180\n[ 2.697393] vfs_read+0x261/0x390\n[ 2.697397] ksys_read+0x71/0xf0\n[ 2.697398] __x64_sys_read+0x19/0x30\n[ 2.697399] x64_sys_call+0x1e88/0x26a0\n[ 2.697405] do_syscall_64+0x80/0x670\n[ 2.697410] ? __x64_sys_newfstat+0x15/0x20\n[ 2.697414] ? x64_sys_call+0x204a/0x26a0\n[ 2.697415] ? do_syscall_64+0xb8/0x670\n[ 2.697417] ? irqentry_exit_to_user_mode+0x2e/0x2a0\n[ 2.697420] ? irqentry_exit+0x43/0x50\n[ 2.697421] ? exc_page_fault+0x90/0x1b0\n[ 2.697422] entry_SYSCALL_64_after_hwframe+0x76/0x7e\n[ 2.697425] RIP: 0033:0x75054cba4a06\n[ 2.697426] Code: 5d e8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 75 19 83 e2 39 83 fa 08 75 11 e8 26 ff ff ff 66 0f 1f 44 00 00 48 8b 45 10 0f 05 <48> 8b 5d f8 c9 c3 0f 1f 40 00 f3 0f 1e fa 55 48 89 e5 48 83 ec 08\n[ 2.697427] RSP: 002b:00007fff973723a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000\n[ 2.697430] RAX: ffffffffffffffda RBX: 00005ea9a2c02760 RCX: 000075054cba4a06\n[ 2.697432] RDX: 0000000000002000 RSI: 000075054c190000 RDI: 000000000000001b\n[ 2.697433] RBP: 00007fff973723c0 R08: 0000000000000000 R09: 0000000000000000\n[ 2.697434] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000\n[ 2.697434] R13: 00005ea9a2c027c0 R14: 00005ea9a2be5608 R15: 00005ea9a2be55f0\n[ 2.697436] \n[ 2.697436] ---[ end trace ]---\n\nThis situation can happen for block devices because when\nCONFIG_TRANSPARENT_HUGEPAGE is enabled, the maximum logical_block_size\nis 64 KiB. set_init_blocksize() then sets the block device\ninode->i_blkbits to 13, which is within this limit.\n\nFile I/O does not trigger this problem because for filesystems that do\nnot support the FS_LBS feature, sb_set_blocksize() prevents\nsb->s_blocksize_bits from being larger than PAGE_SHIFT. During inode\nallocation, alloc_inode()->inode_init_always() assigns inode->i_blkbits\nfrom sb->s_blocksize_bits. Currently, only xfs_fs_type has the FS_LBS\nflag, and since xfs I/O paths do not reach submit_bh_wbc(), it does not\nhit the left-shift underflow issue.\n\n[EB: use folio_pos() and consolidate the two shifts by i_blkbits]" } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/crypto/inline_crypt.c" ], "versions": [ { "version": "47dd67532303803a87f43195e088b3b4bcf0454d", "lessThan": "dde026c5d2a5870f97924d5b512adf2b93fb7153", "status": "affected", "versionType": "git" }, { "version": "47dd67532303803a87f43195e088b3b4bcf0454d", "lessThan": "1e39da974ce621ed874c6d3aaf65ad14848c9f0d", "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/crypto/inline_crypt.c" ], "versions": [ { "version": "6.15", "status": "affected" }, { "version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.8", "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": "6.15", "versionEndExcluding": "6.17.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/dde026c5d2a5870f97924d5b512adf2b93fb7153" }, { "url": "https://git.kernel.org/stable/c/1e39da974ce621ed874c6d3aaf65ad14848c9f0d" } ], "title": "fscrypt: fix left shift underflow when inode->i_blkbits > PAGE_SHIFT", "x_generator": { "engine": "bippy-1.2.0" } } } }