{"id":"CVE-2026-64027","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-64027","generatedAt":"2026-10-28T08:28:00.667Z","title":"In the Linux kernel, the following vulnerability has been resolved: net: shaper: rework the VALID marking (again) Recent commit changed the semantics from NOT_VALID to VALID.","description":"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.","published":"2026-07-19T16:17:43.000Z","lastModified":"2026-10-19T21:17:20.000Z","status":"Modified","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-362"],"affected":["linux/linux kernel"],"epss":{"score":0.00134,"percentile":0.02873,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.13%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/2417df5e7bb4184b9d3a2988036bf2c46e594545","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/96ea960dd40fd55302e0fd755176f26a95e6a50c","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b8d7519352ba8c6df83259295d4a3bad093cae90","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64027","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}