{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2025-40295 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-40295 is a vulnerability in Linux, published on 8 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2025-40295 and fix it if it is affected.\n\nWhat it is: CVE-2025-40295 is a vulnerability in Linux, published on 8 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2025-40295 in the wild and no public exploit code.\n\nAffected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2025-40295/ (Markdown: https://insights.sbomify.com/CVE-2025-40295/index.md)","id":"CVE-2025-40295","markdown":"https://insights.sbomify.com/CVE-2025-40295/index.md","name":"CVE-2025-40295","record":{"aliases":["BELL-CVE-2025-40295","DEBIAN-CVE-2025-40295","GHSA-h3fq-7jwc-95rx","UBUNTU-CVE-2025-40295"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel","requires_auth":"none","summary":"A local attacker can trigger a kernel crash via UBSAN warning when using specific block sizes with fscrypt, requiring a patched kernel.","user_interaction":"not_required","vuln_class":"integer_overflow"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfscrypt: fix left shift underflow when inode-\u003ei_blkbits \u003e 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-\u003ei_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]  \u003cTASK\u003e\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 \u003c48\u003e 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]  \u003c/TASK\u003e\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-\u003ei_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-\u003es_blocksize_bits from being larger than PAGE_SHIFT. During inode\nallocation, alloc_inode()-\u003einode_init_always() assigns inode-\u003ei_blkbits\nfrom sb-\u003es_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]","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"fscrypt: fix left shift underflow when inode-\u003ei_blkbits \u003e PAGE_SHIFT","id":"CVE-2025-40295","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"integer_overflow","year":"2025"},"n_packages":0,"n_references":2,"next":{"headline":"platform/x86: int3472: Fix double free of GPIO device during unregister","id":"CVE-2025-40296"},"packages":[],"prev":{"headline":"Bluetooth: MGMT: Fix OOB access in parse_adv_monitor_pattern()","id":"CVE-2025-40294"},"products":["Linux"],"published":"2025-12-08","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-05-11","vendors":["Linux"]},"summary":"A local attacker can trigger a kernel crash via UBSAN warning when using specific block sizes with fscrypt, requiring a patched kernel.","url":"https://insights.sbomify.com/CVE-2025-40295/"}