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CVE-2018-12633

An issue was discovered in the Linux kernel through 4.17.2. vbg_misc_device_ioctl() in drivers...

6.3 MediumPublic exploitFix available

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

0.26%Down 0.3 points since Apr 14, 2021
90%50%10%1%

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 MediumCVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H
CVSS 2.0
6.3 MediumAV: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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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 HighCVSS: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 MediumCVSS: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

Affected packages
PackageAffectedFixed
linux
Debian:12
before 4.17.3-1
4.17.3-1
linux
Debian:13
before 4.17.3-1
4.17.3-1
linux
Debian:14
before 4.17.3-1
4.17.3-1
virtualbox
Ubuntu: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 less
5.0.10-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
virtualbox
Ubuntu: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 less
5.2.2-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
virtualbox
Ubuntu: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 less
6.1.2-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-realtime
Ubuntu:22.04:LTS
All versions, plus listed versions
5.15.0-1073.75
None known
linux-realtime
Ubuntu:22.04:LTS
All versions, plus listed versions
5.15.0-1032.35
None known
virtualbox
Ubuntu: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 less
6.1.34-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-realtime
Ubuntu:24.04:LTS
All versions, plus listed versions
6.8.0-2019.20
None known
Show 4 moreShow less
Affected packages
PackageAffectedFixed
virtualbox
Ubuntu: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 less
7.0.14-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
virtualbox
Ubuntu: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 less
7.1.10-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
virtualbox
Ubuntu: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
virtualbox
Ubuntu: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 less
7.2.4-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.

Public exploits
SourceLinkDate
PoC in GitHubwiliam227user/CVE-2018-12633-TPLink-Auth-Bypass2025-12-31

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE 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

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