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Fencer Vulns
medium 4.4

CVE-2020-16123 json

Bypass of snapd pulseaudio restrictions

published 2020-12-03 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-8089

cvss
4.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

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.

Patch / fix

  • Canonical pulseaudio 1:8.0-0ubuntu3.15, 1:11.1-1ubuntu7.11, 1:13.99.1-1ubuntu3.8, 1:13.99.2-1ubuntu2.1, 1:13.99.3-1ubuntu2
  • pulseaudio Ubuntu 16.04 LTS 1:8.0-0ubuntu3.15
  • pulseaudio Ubuntu 18.04 LTS 1:11.1-1ubuntu7.11
  • pulseaudio Ubuntu 20.04 LTS 1:13.99.1-1ubuntu3.8

ubuntu advisories UBUNTU-CVE-2020-16123

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-16123 updated cvss 5.9

pulseaudio: race condition in snap policy module allows for information exposure

  • Red Hat Enterprise Linux 6 pulseaudio, pulseaudio-libs, pulseaudio-utils, pulseaudio-gdm-hooks, pulseaudio-libs-glib2, pulseaudio-module-x11, +5 more Red Hat Enterprise Linux 7 pulseaudio, pulseaudio-libs, pulseaudio-qpaeq, pulseaudio-utils, pulseaudio-gdm-hooks, pulseaudio-libs-glib2, +5 more Red Hat Enterprise Linux 8 pulseaudio, pulseaudio-libs, pulseaudio-utils, pulseaudio-libs-glib2, pulseaudio-module-x11, pulseaudio-module-bluetooth
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • launchpad.net https://launchpad.net/bugs/1895928 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.4 CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:N
NVD 3.1 4.7 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:P/I:N/A:N

Affected products

  • Canonical pulseaudio

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.