{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2023-53440 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2023-53440 is a high-severity vulnerability in Linux kernel, published on 18 Sep 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-2023-53440 and fix it if it is affected.\n\nWhat it is: CVE-2023-53440 is a high-severity vulnerability in Linux kernel, published on 18 Sep 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-2023-53440 in the wild and no public exploit code.\n\nAffected product: Linux kernel. 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-2023-53440/ (Markdown: https://insights.sbomify.com/CVE-2023-53440/index.md)","id":"CVE-2023-53440","markdown":"https://insights.sbomify.com/CVE-2023-53440/index.md","name":"CVE-2023-53440","record":{"aliases":["BELL-CVE-2023-53440","DEBIAN-CVE-2023-53440","GHSA-v99g-2hwc-34c3","UBUNTU-CVE-2023-53440"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel filesystem","requires_auth":"low_privilege","summary":"A local attacker can trigger a null pointer dereference or use-after-free in the nilfs2 filesystem by accessing sysfs attributes, causing a system crash.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-476","name":"NULL Pointer Dereference"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix sysfs interface lifetime\n\nThe current nilfs2 sysfs support has issues with the timing of creation\nand deletion of sysfs entries, potentially leading to null pointer\ndereferences, use-after-free, and lockdep warnings.\n\nSome of the sysfs attributes for nilfs2 per-filesystem instance refer to\nmetadata file \"cpfile\", \"sufile\", or \"dat\", but\nnilfs_sysfs_create_device_group that creates those attributes is executed\nbefore the inodes for these metadata files are loaded, and\nnilfs_sysfs_delete_device_group which deletes these sysfs entries is\ncalled after releasing their metadata file inodes.\n\nTherefore, access to some of these sysfs attributes may occur outside of\nthe lifetime of these metadata files, resulting in inode NULL pointer\ndereferences or use-after-free.\n\nIn addition, the call to nilfs_sysfs_create_device_group() is made during\nthe locking period of the semaphore \"ns_sem\" of nilfs object, so the\nshrinker call caused by the memory allocation for the sysfs entries, may\nderive lock dependencies \"ns_sem\" -\u003e (shrinker) -\u003e \"locks acquired in\nnilfs_evict_inode()\".\n\nSince nilfs2 may acquire \"ns_sem\" deep in the call stack holding other\nlocks via its error handler __nilfs_error(), this causes lockdep to report\ncircular locking.  This is a false positive and no circular locking\nactually occurs as no inodes exist yet when\nnilfs_sysfs_create_device_group() is called.  Fortunately, the lockdep\nwarnings can be resolved by simply moving the call to\nnilfs_sysfs_create_device_group() out of \"ns_sem\".\n\nThis fixes these sysfs issues by revising where the device's sysfs\ninterface is created/deleted and keeping its lifetime within the lifetime\nof the metadata files above.","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":"nilfs2: fix sysfs interface lifetime","id":"CVE-2023-53440","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"null_dereference","year":"2023"},"n_packages":0,"n_references":8,"next":{"headline":"bpf: cpumap: Fix memory leak in cpu_map_update_elem","id":"CVE-2023-53441"},"packages":[],"prev":{"headline":"net: skb_partial_csum_set() fix against transport header magic value","id":"CVE-2023-53439"},"products":["Linux"],"published":"2025-09-18","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"A local attacker can trigger a null pointer dereference or use-after-free in the nilfs2 filesystem by accessing sysfs attributes, causing a system crash.","url":"https://insights.sbomify.com/CVE-2023-53440/"}