CVE-2018-12633
An issue was discovered in the Linux kernel through 4.17.2. vbg_misc_device_ioctl() in drivers...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
6.3
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.
- Record
CVE-2018-12633- CVSS 3.0
- 6.3 Medium
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H - CVSS 2.0
- 6.3 Medium
AV:L/AC:M/Au:N/C:C/I:N/A:C - Weakness
- CWE-362
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2018-12633- Updated
- 2026-11-02
EUVDEUVD-2018-4589 No score
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.
- Record
EUVD-2018-4589- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-9rwp-mqvh-8g6q
6.3
An issue was discovered in the Linux kernel through 4.17.2. vbg_misc_device_ioctl() in drivers...
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.
- Record
GHSA-9rwp-mqvh-8g6q- CVSS 3.0
- 6.3 Medium
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H - Weakness
- CWE-362
- Updated
- 2026-11-02
OSV
6.3
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.
- Record
CVE-2018-12633- CVSS 3.0
- 6.3 Medium
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2018-12633
6.3
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.
- Record
DEBIAN-CVE-2018-12633- CVSS 3.0
- 6.3 Medium
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2018-12633
7.3
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.
- Record
UBUNTU-CVE-2018-12633- CVSS 4.0
- 7.3 High
CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - CVSS 3.0
- 6.3 Medium
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
linuxDebian:12 |
before 4.17.3-1 | 4.17.3-1 |
linuxDebian:13 |
before 4.17.3-1 | 4.17.3-1 |
linuxDebian:14 |
before 4.17.3-1 | 4.17.3-1 |
virtualboxUbuntu:16.04:LTS |
All versions, plus listed versions 5.0.4-dfsg-25.0.8-dfsg-15.0.10-dfsg-15.0.10-dfsg-25.0.10-dfsg-3 Show 25 moreShow less5.0.10-dfsg-45.0.10-dfsg-55.0.10-dfsg-65.0.10-dfsg-75.0.12-dfsg-15.0.12-dfsg-25.0.14-dfsg-15.0.14-dfsg-25.0.14-dfsg-2build15.0.16-dfsg-25.0.16-dfsg-35.0.18-dfsg-15.0.18-dfsg-1ubuntu15.0.18-dfsg-25.0.18-dfsg-2build15.0.18-dfsg-2ubuntu15.0.24-dfsg-0ubuntu1.16.04.15.0.32-dfsg-0ubuntu1.16.04.25.0.36-dfsg-0ubuntu1.16.04.25.0.40-dfsg-0ubuntu1.16.04.15.0.40-dfsg-0ubuntu1.16.04.25.1.34-dfsg-0ubuntu1.16.04.25.1.38-dfsg-0ubuntu1.16.04.15.1.38-dfsg-0ubuntu1.16.04.25.1.38-dfsg-0ubuntu1.16.04.3 |
None known |
virtualboxUbuntu:18.04:LTS |
All versions, plus listed versions 5.1.30-dfsg-15.2.0-dfsg-1build25.2.0-dfsg-25.2.0-dfsg-45.2.0-dfsg-5 Show 26 moreShow less5.2.2-dfsg-25.2.2-dfsg-3~build15.2.2-dfsg-35.2.4-dfsg-15.2.4-dfsg-25.2.6-dfsg-15.2.6-dfsg-25.2.6-dfsg-35.2.6-dfsg-3build15.2.6-dfsg-55.2.8-dfsg-25.2.8-dfsg-35.2.8-dfsg-55.2.8-dfsg-65.2.8-dfsg-75.2.10-dfsg-15.2.10-dfsg-25.2.10-dfsg-55.2.10-dfsg-65.2.10-dfsg-6ubuntu18.04.15.2.18-dfsg-2~ubuntu18.04.15.2.18-dfsg-2~ubuntu18.04.35.2.18-dfsg-2~ubuntu18.04.55.2.32-dfsg-0~ubuntu18.04.15.2.34-dfsg-0~ubuntu18.04.15.2.42-dfsg-0~ubuntu1.18.04.1 |
None known |
virtualboxUbuntu:20.04:LTS |
All versions, plus listed versions 6.0.14-dfsg-16.0.14-dfsg-2~build16.0.14-dfsg-26.1.0-dfsg-3build16.1.0-dfsg-3build2 Show 18 moreShow less6.1.2-dfsg-16.1.2-dfsg-1build16.1.4-dfsg-16.1.4-dfsg-2~build16.1.4-dfsg-26.1.4-dfsg-46.1.6-dfsg-16.1.10-dfsg-1~ubuntu1.20.04.16.1.16-dfsg-6~ubuntu1.20.04.16.1.16-dfsg-6~ubuntu1.20.04.26.1.22-dfsg-2~ubuntu1.20.04.16.1.26-dfsg-3~ubuntu1.20.04.16.1.26-dfsg-3~ubuntu1.20.04.26.1.32-dfsg-1~ubuntu1.20.04.16.1.34-dfsg-3~ubuntu1.20.04.16.1.38-dfsg-3~ubuntu1.20.04.16.1.48-dfsg-1~ubuntu1.20.04.16.1.50-dfsg-1~ubuntu1.20.04.1 |
None known |
linux-intel-iot-realtimeUbuntu:22.04:LTS |
All versions, plus listed versions 5.15.0-1073.75 |
None known |
linux-realtimeUbuntu:22.04:LTS |
All versions, plus listed versions 5.15.0-1032.35 |
None known |
virtualboxUbuntu:22.04:LTS |
All versions, plus listed versions 6.1.26-dfsg-46.1.28-dfsg-16.1.30-dfsg-16.1.32-dfsg-16.1.32-dfsg-1build1 Show 5 moreShow less6.1.34-dfsg-3~ubuntu1.22.04.16.1.38-dfsg-3~ubuntu1.22.04.16.1.48-dfsg-1~ubuntu1.22.04.16.1.50-dfsg-1~ubuntu1.22.04.16.1.50-dfsg-1~ubuntu1.22.04.3 |
None known |
linux-raspi-realtimeUbuntu:24.04:LTS |
All versions, plus listed versions 6.8.0-2019.20 |
None known |
Show 4 moreShow less
| Package | Affected | Fixed |
|---|---|---|
virtualboxUbuntu:24.04:LTS |
All versions, plus listed versions 7.0.10-dfsg-37.0.12-dfsg-17.0.12-dfsg-1build17.0.14-dfsg-17.0.14-dfsg-2 Show 8 moreShow less7.0.14-dfsg-47.0.14-dfsg-4build47.0.14-dfsg-4build57.0.16-dfsg-17.0.16-dfsg-27.0.16-dfsg-2ubuntu17.0.16-dfsg-2ubuntu1.17.0.16-dfsg-2ubuntu1.3 |
None known |
virtualboxUbuntu:25.10 |
All versions, plus listed versions 7.0.20-dfsg-1.27.0.26-dfsg-17.1.8-dfsg-27.1.8-dfsg-37.1.8-dfsg-3build1 Show 7 moreShow less7.1.10-dfsg-17.1.12-dfsg-17.1.12-dfsg-27.2.0-dfsg-27.2.0-dfsg-37.2.2-dfsg-27.2.2-dfsg-2ubuntu0.1 |
None known |
virtualboxUbuntu:26.10 |
All versions, plus listed versions 7.2.6-dfsg-47.2.8-dfsg-17.2.14-dfsg-37.2.16-dfsg-17.2.18-dfsg-17.2.20-dfsg-17.2.20-dfsg-2 |
None known |
virtualboxUbuntu:26.04:LTS |
All versions, plus listed versions 7.2.2-dfsg-27.2.2-dfsg-37.2.4-dfsg-17.2.4-dfsg-1build17.2.4-dfsg-2~build1 Show 5 moreShow less7.2.4-dfsg-37.2.6-dfsg-37.2.6-dfsg-3ubuntu17.2.6-dfsg-3.27.2.6-dfsg-4 |
None known |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | wiliam227user/CVE-2018-12633-TPLink-Auth-Bypass | 2025-12-31 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2018-12633 is a medium vulnerability (CVSS 6.3) in Linux Kernel, published June 22, 2018. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 0.26%, the 17th percentile. Fixed in linux 4.17.3-1.
References
bugzilla.kernel.org/show_bug.cgi?id=200131
github.com/torvalds/linux/commit/bd23a7269834dc7c1f93e83535d16ebc44b75eba
git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit?id=bd23a7269834dc7c1f93e83535d16ebc44b75eba
nvd.nist.gov/vuln/detail/CVE-2018-12633
github.com/advisories/GHSA-9rwp-mqvh-8g6q
security-tracker.debian.org/tracker/CVE-2018-12633
ubuntu.com/security/CVE-2018-12633
cve.org/CVERecord?id=CVE-2018-12633