{"id":"CVE-2026-64059","summary":"netfs: Fix folio-\u003eprivate handling in netfs_perform_write()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix folio-\u003eprivate handling in netfs_perform_write()\n\nUnder some circumstances, netfs_perform_write() doesn't correctly\nmanipulate folio-\u003eprivate between NULL, NETFS_FOLIO_COPY_TO_CACHE, pointing\nto a group and pointing to a netfs_folio struct, leading to potential\nmultiple attachments of private data with associated folio ref leaks and\nalso leaks of netfs_folio structs or netfs_group refs.\n\nFix this by consolidating the place at which a folio is marked uptodate in\none place and having that look at what's attached to folio-\u003eprivate and\ndecide how to clean it up and then set the new group.  Also, the content\nshouldn't be flushed if group is NULL, even if a group is specified in the\nnetfs_group parameter, as that would be the case for a new folio.  A\nfilesystem should always specify netfs_group or never specify netfs_group.\n\nThe Sashiko auto-review tool noted that it was theoretically possible that\nthe fpos \u003e= ctx-\u003ezero_point section might leak if it modified a streaming\nwrite folio.  This is unlikely, but with a network filesystem, third party\nchanges can happen.  It also pointed out that __netfs_set_group() would\nleak if called multiple times on the same folio from the \"whole folio\nmodify section\".","modified":"2026-07-21T03:47:52.015187774Z","published":"2026-07-19T15:39:39.607Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64059.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0969ea8370bad0e4fb6131b6a7bed9e7ec522ac7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/551b5c71ee312ca7646ddb605231c1016e8cbb18"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7f040243c74d72b45b22246c7d9e621fbeab44ac"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ccde2ac757c713535b224233a296de40efe5212d"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64059.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64059"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"8f52de0077ba3bf41e5d53d67a185700f41efce7"},{"fixed":"7f040243c74d72b45b22246c7d9e621fbeab44ac"},{"fixed":"551b5c71ee312ca7646ddb605231c1016e8cbb18"},{"fixed":"0969ea8370bad0e4fb6131b6a7bed9e7ec522ac7"},{"fixed":"ccde2ac757c713535b224233a296de40efe5212d"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64059.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.12.0"},{"fixed":"6.12.92"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.34"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64059.json"}}],"schema_version":"1.7.5"}