{"id":"CVE-2026-64027","summary":"net: shaper: rework the VALID marking (again)","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: shaper: rework the VALID marking (again)\n\nRecent commit changed the semantics from NOT_VALID to VALID.\nI didn't realize that the flags are not stored atomically\nwith the entry in XArray. There's still a race of reader\nobserving a VALID mark for a slot, getting interrupted,\nwriter replacing the entry with a different one, reader\ncontinuing, fetching the entry which is now a different\npointer than the pointer for which VALID was meant.\n\nThe biggest consequence of this is that we may see a UAF\nsince net_shaper_rollback() assumed that entries without\nVALID can be freed without observing RCU.\n\nLooks like the XArray marks are buying us nothing at this\npoint. Let's convert the code to an explicit valid field.\nThe smp_load_acquire() / smp_store_release() barriers are\nmarginally cleaner.","modified":"2026-07-22T05:29:53.378718887Z","published":"2026-07-19T15:39:18.470Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64027.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2417df5e7bb4184b9d3a2988036bf2c46e594545"},{"type":"WEB","url":"https://git.kernel.org/stable/c/96ea960dd40fd55302e0fd755176f26a95e6a50c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b8d7519352ba8c6df83259295d4a3bad093cae90"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64027.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64027"},{"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":"93954b40f6a4fc43226c01a15b02732f884500f1"},{"fixed":"2417df5e7bb4184b9d3a2988036bf2c46e594545"},{"fixed":"96ea960dd40fd55302e0fd755176f26a95e6a50c"},{"fixed":"b8d7519352ba8c6df83259295d4a3bad093cae90"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64027.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"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-2026-64027.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}