{"id":"CVE-2025-39816","url":"https://www.cyber-defence.io/tools/cve/CVE-2025-39816","generatedAt":"2026-10-28T04:45:56.081Z","title":"In the Linux kernel, the following vulnerability has been resolved: io_uring/kbuf: always use READ_ONCE() to read ring provided buffer lengths Since the buffers are mapped from userspace, it is prudent to use READ_ONCE() to read the value into a local…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/kbuf: always use READ_ONCE() to read ring provided buffer lengths\n\nSince the buffers are mapped from userspace, it is prudent to use\nREAD_ONCE() to read the value into a local variable, and use that for\nany other actions taken. Having a stable read of the buffer length\navoids worrying about it changing after checking, or being read multiple\ntimes.\n\nSimilarly, the buffer may well change in between it being picked and\nbeing committed. Ensure the looping for incremental ring buffer commit\nstops if it hits a zero sized buffer, as no further progress can be made\nat that point.","published":"2025-09-16T13:15:57.000Z","lastModified":"2026-10-19T21:10:00.000Z","status":"Modified","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":[],"affected":["linux/linux kernel"],"epss":{"score":0.00148,"percentile":0.03971,"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":"low","text":"Lower severity and a low EPSS score (0.15%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/390a61d284e1ced088d43928dfcf6f86fffdd780","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/695673eb5711ee5eb1769481cf1503714716a7d1","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/91f262ea2a76a02d9e37dba6637cfe6feebb20a8","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/98b6fa62c84f2e129161e976a5b9b3cb4ccd117b","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-39816","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."}