CVE intelligence and bounded remediation
CVE-2020-16123 — Canonical Ubuntu Linux security vulnerability
An Ubuntu-specific patch in PulseAudio created a race condition where the snap policy module would fail to identify a client connection from a snap as coming from a snap if SCM_CREDENTIALS were missing, allowing the snap to connect to PulseAudio without proper confinement. This could be exploited by an attacker to expose sensitive information. Fixed in 1:13.99.3-1ubuntu2, 1:13.99.2-1ubuntu2.1, 1:13.99.1-1ubuntu3.8, 1:11.1-1ubuntu7.11, and 1:8.0-0ubuntu3.15.
- Severity
- Medium
- CVSS
- 4.7 (3.1)
- Published
- 2020-12-04
- CISA KEV
- Not currently listed
- Ecosystem
- operating-system
- Weaknesses
- CWE-362
Affected products
- canonical / ubuntu_linux / 16.04
- canonical / ubuntu_linux / 18.04
- canonical / ubuntu_linux / 20.04
- canonical / ubuntu_linux / 20.10
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
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