{"id":"CVE-2018-12633","url":"https://www.cyber-defence.io/tools/cve/CVE-2018-12633","generatedAt":"2026-10-28T20:12:24.816Z","title":"The header part of the user data is double-fetched, and a malicious user thread can tamper with the critical variables (hdr.size_in and hdr.size_out) in the header between the two fetches because of a race condition, leading to severe kernel errors,…","description":"An issue was discovered in the Linux kernel through 4.17.2. vbg_misc_device_ioctl() in drivers/virt/vboxguest/vboxguest_linux.c reads the same user data twice with copy_from_user. The header part of the user data is double-fetched, and a malicious user thread can tamper with the critical variables (hdr.size_in and hdr.size_out) in the header between the two fetches because of a race condition, leading to severe kernel errors, such as buffer over-accesses. This bug can cause a local denial of service and information leakage.","published":"2018-06-22T00:29:00.000Z","lastModified":"2026-06-17T01:38:06.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.0","score":6.3,"severity":"MEDIUM","vector":"CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H"},"cwe":["CWE-362"],"affected":["linux/linux kernel"],"epss":{"score":0.00264,"percentile":0.18271,"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 (0.26%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bd23a7269834dc7c1f93e83535d16ebc44b75eba","tags":["Patch","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://bugzilla.kernel.org/show_bug.cgi?id=200131","tags":["Issue Tracking","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/torvalds/linux/commit/bd23a7269834dc7c1f93e83535d16ebc44b75eba","tags":["Patch","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bd23a7269834dc7c1f93e83535d16ebc44b75eba","tags":["Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://bugzilla.kernel.org/show_bug.cgi?id=200131","tags":["Issue Tracking","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/torvalds/linux/commit/bd23a7269834dc7c1f93e83535d16ebc44b75eba","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2018-12633","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."}