CVE-2018-12633
Publication date 22 June 2018
Last updated 28 August 2025
Ubuntu priority
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.
Patch details
| Package | Patch details |
|---|
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score |
6.3 · Medium
|
| Attack vector | Local |
| Attack complexity | High |
| Privileges required | Low |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity impact | None |
| Availability impact | High |
| Vector | CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H |