{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-64064 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-64064 is a medium-severity vulnerability in Linux kernel, published on 19 Jul 2026. 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-2026-64064 and fix it if it is affected.\n\nWhat it is: CVE-2026-64064 is a medium-severity vulnerability in Linux kernel, published on 19 Jul 2026. 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-2026-64064 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-2026-64064/ (Markdown: https://insights.sbomify.com/CVE-2026-64064/index.md)","id":"CVE-2026-64064","markdown":"https://insights.sbomify.com/CVE-2026-64064/index.md","name":"CVE-2026-64064","record":{"aliases":["BELL-CVE-2026-64064","DEBIAN-CVE-2026-64064","GHSA-gxmr-cf3v-qq46","UBUNTU-CVE-2026-64064"],"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":"low_privilege","summary":"A null pointer dereference in the Linux kernel netfs subsystem can cause a system crash when specific file operations are performed with caching disabled.","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":5.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix netfs_invalidate_folio() to clear dirty bit if all changes gone\n\nIf a streaming write is made, this will leave the relevant modified folio\nin a not-uptodate, but dirty state with a netfs_folio struct hung off of\nfolio-\u003eprivate indicating the dirty range.  Subsequently truncating the\nfile such that the dirty data in the folio is removed, but the first part\nof the folio theoretically remains will cause the netfs_folio struct to be\ndiscarded... but will leave the dirty flag set.\n\nIf the folio is then read via mmap(), netfs_read_folio() will see that the\npage is dirty and jump to netfs_read_gaps() to fill in the missing bits.\nnetfs_read_gaps(), however, expects there to be a netfs_folio struct\npresent and can oops because truncate removed it.\n\nFix this by calling folio_cancel_dirty() in netfs_invalidate_folio() in the\nevent that all the dirty data in the folio is erased (as nfs does).\n\nAlso add some tracepoints to log modifications to a dirty page.\n\nThis can be reproduced with something like:\n\n    dd if=/dev/zero of=/xfstest.test/foo bs=1M count=1\n    umount /xfstest.test\n    mount /xfstest.test\n    xfs_io -c \"w 0xbbbf 0xf96c\" \\\n           -c \"truncate 0xbbbf\" \\\n           -c \"mmap -r 0xb000 0x11000\" \\\n           -c \"mr 0xb000 0x11000\" \\\n           /xfstest.test/foo\n\nwith fscaching disabled (otherwise streaming writes are suppressed) and a\nchange to netfs_perform_write() to disallow streaming writes if the fd is\nopen O_RDWR:\n\n\tif (//(file-\u003ef_mode \u0026 FMODE_READ) || \u003c--- comment this out\n\t    netfs_is_cache_enabled(ctx)) {\n\nIt should be reproducible even without this change, but if prevents the\nabove trivial xfs_io command from reproducing it.\n\nNote that the initial dd is important: the file must start out sufficiently\nlarge that the zero-point logic doesn't just clear the gaps because it\nknows there's nothing in the file to read yet.  Unmounting and mounting is\nneeded to clear the pagecache (there are other ways to do that that may\nalso work).\n\nThis was initially reproduced with the generic/522 xfstest on some patches\nthat remove the FMODE_READ restriction.","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":"netfs: Fix netfs_invalidate_folio() to clear dirty bit if all changes gone","id":"CVE-2026-64064","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"null_dereference","year":"2026"},"n_packages":0,"n_references":4,"next":{"headline":"netfs: fix VM_BUG_ON_FOLIO() issue in netfs_write_begin() call","id":"CVE-2026-64065"},"packages":[],"prev":{"headline":"netfs: Fix streaming write being overwritten","id":"CVE-2026-64063"},"products":["Linux"],"published":"2026-07-19","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":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-07-19","vendors":["Linux"]},"summary":"A null pointer dereference in the Linux kernel netfs subsystem can cause a system crash when specific file operations are performed with caching disabled.","url":"https://insights.sbomify.com/CVE-2026-64064/"}