CVE intelligence and bounded remediation
CVE-2018-12633 — An issue was discovered in the Linux kernel through 4.17.2
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.
- Severity
- Medium
- CVSS
- 6.3 (3.0)
- Published
- 2018-06-22
- CISA KEV
- Not currently listed
- Ecosystem
- linux/kernel
- Weaknesses
- CWE-362
Affected products
- linux / linux_kernel
Matched remediation archetype
Race condition, TOCTOU, and lifecycle synchronization
This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.
Check exposure
- Map concurrent actors, shared state, lock boundaries, signals, callbacks, retries, and check-then-use sequences in the affected path.
- Determine whether untrusted users can influence timing, object names, filesystem state, or repeated state transitions.
- Identify clustered and multi-process behavior that repository-local tests may not represent.
Remediate safely
- Make the sensitive state transition atomic or protect it with a consistently ordered synchronization primitive.
- Perform authorization and invariant checks on the same authoritative object and transaction used for the operation.
- Use unique private resources, safe ownership transfer, and idempotent operations; add deterministic concurrency regression tests.
Authoritative sources
Complete CVE record and remediation plan
The detailed catalog view below loads this exact record, its source evidence, and the full seven-phase agentic change plan.