CVE intelligence and bounded remediation

CVE-2021-20261 — A race condition was found in the Linux kernels implementation of the floppy disk drive controller driver software

Medium CVSS 6.4

A race condition was found in the Linux kernels implementation of the floppy disk drive controller driver software. The impact of this issue is lessened by the fact that the default permissions on the floppy device (/dev/fd0) are restricted to root. If the permissions on the device have changed the impact changes greatly. In the default configuration root (or equivalent) permissions are required to attack this flaw.

Severity
Medium
CVSS
6.4 (3.1)
Published
2021-03-11
CISA KEV
Not currently listed
Ecosystem
linux/kernel
Weaknesses
CWE-362

Affected products

  • linux / linux_kernel
  • linux / linux_kernel / 4.5
  • redhat / enterprise_linux / 7.0

Showing 3 representative product identities from 7 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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