{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2025-40138 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-40138 is a vulnerability in Linux, published on 12 Nov 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-2025-40138 and fix it if it is affected.\n\nWhat it is: CVE-2025-40138 is a vulnerability in Linux, published on 12 Nov 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-2025-40138 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-2025-40138/ (Markdown: https://insights.sbomify.com/CVE-2025-40138/index.md)","id":"CVE-2025-40138","markdown":"https://insights.sbomify.com/CVE-2025-40138/index.md","name":"CVE-2025-40138","record":{"aliases":["BELL-CVE-2025-40138","GHSA-p3hr-r37g-j63r","UBUNTU-CVE-2025-40138"],"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":"high_privilege","summary":"A local attacker with root privileges can cause a kernel crash via a NULL pointer dereference in the f2fs filesystem during remount operations.","user_interaction":"not_required","vuln_class":"null_dereference"},"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\nf2fs: fix to avoid NULL pointer dereference in f2fs_check_quota_consistency()\n\nsyzbot reported a f2fs bug as below:\n\nOops: gen[  107.736417][ T5848] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI\nKASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]\nCPU: 1 UID: 0 PID: 5848 Comm: syz-executor263 Tainted: G        W           6.17.0-rc1-syzkaller-00014-g0e39a731820a #0 PREEMPT_{RT,(full)}\nRIP: 0010:strcmp+0x3c/0xc0 lib/string.c:284\nCall Trace:\n \u003cTASK\u003e\n f2fs_check_quota_consistency fs/f2fs/super.c:1188 [inline]\n f2fs_check_opt_consistency+0x1378/0x2c10 fs/f2fs/super.c:1436\n __f2fs_remount fs/f2fs/super.c:2653 [inline]\n f2fs_reconfigure+0x482/0x1770 fs/f2fs/super.c:5297\n reconfigure_super+0x224/0x890 fs/super.c:1077\n do_remount fs/namespace.c:3314 [inline]\n path_mount+0xd18/0xfe0 fs/namespace.c:4112\n do_mount fs/namespace.c:4133 [inline]\n __do_sys_mount fs/namespace.c:4344 [inline]\n __se_sys_mount+0x317/0x410 fs/namespace.c:4321\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nThe direct reason is f2fs_check_quota_consistency() may suffer null-ptr-deref\nissue in strcmp().\n\nThe bug can be reproduced w/ below scripts:\nmkfs.f2fs -f /dev/vdb\nmount -t f2fs -o usrquota /dev/vdb /mnt/f2fs\nquotacheck -uc /mnt/f2fs/\numount /mnt/f2fs\nmount -t f2fs -o usrjquota=aquota.user,jqfmt=vfsold /dev/vdb /mnt/f2fs\nmount -t f2fs -o remount,usrjquota=,jqfmt=vfsold /dev/vdb /mnt/f2fs\numount /mnt/f2fs\n\nSo, before old_qname and new_qname comparison, we need to check whether\nthey are all valid pointers, fix it.","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":"f2fs: fix to avoid NULL pointer dereference in f2fs_check_quota_consistency()","id":"CVE-2025-40138","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"null_dereference","year":"2025"},"n_packages":0,"n_references":2,"next":{"headline":"smc: Use __sk_dst_get() and dst_dev_rcu() in in smc_clc_prfx_set().","id":"CVE-2025-40139"},"packages":[],"prev":{"headline":"f2fs: fix to truncate first page in error path of f2fs_truncate()","id":"CVE-2025-40137"},"products":["Linux"],"published":"2025-11-12","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 with root privileges can cause a kernel crash via a NULL pointer dereference in the f2fs filesystem during remount operations.","url":"https://insights.sbomify.com/CVE-2025-40138/"}