CVE intelligence and bounded remediation

CVE-2023-2612 — Canonical Ubuntu Linux security vulnerability

Medium CVSS 4.7

Jean-Baptiste Cayrou discovered that the shiftfs file system in the Ubuntu Linux kernel contained a race condition when handling inode locking in some situations. A local attacker could use this to cause a denial of service (kernel deadlock).

Severity
Medium
CVSS
4.7 (3.1)
Published
2023-05-31
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-667

Affected products

  • canonical / ubuntu_linux / 20.04
  • canonical / ubuntu_linux / 22.04
  • canonical / ubuntu_linux / 22.10

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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