CVE intelligence and bounded remediation

CVE-2018-16872 — A flaw was found in qemu Media Transfer Protocol (MTP)

Medium CVSS 5.3

A flaw was found in qemu Media Transfer Protocol (MTP). The code opening files in usb_mtp_get_object and usb_mtp_get_partial_object and directories in usb_mtp_object_readdir doesn't consider that the underlying filesystem may have changed since the time lstat(2) was called in usb_mtp_object_alloc, a classical TOCTTOU problem. An attacker with write access to the host filesystem shared with a guest can use this property to navigate the host filesystem in the context of the QEMU process and read any file the QEMU process has access to. Access to the filesystem may be local or via a network share protocol such as CIFS.

Severity
Medium
CVSS
5.3 (3.1)
Published
2018-12-13
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-367

Affected products

  • qemu / qemu
  • debian / debian_linux / 8.0
  • debian / debian_linux / 9.0
  • fedoraproject / fedora / 29
  • fedoraproject / fedora / 30
  • canonical / ubuntu_linux / 14.04

Showing 6 representative product identities from 10 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Race condition, TOCTOU, and lifecycle synchronization

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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

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