CVE-2020-16123

04.12.2020, 00:15

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.

Race Condition

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	NIST	4.4 MEDIUM	LOCAL	HIGH	LOW	CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:N
canonical	CNA	4.4 MEDIUM	LOCAL	HIGH	LOW	CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:N
CVE	ADP	---				---

Base Score

CVSS 3.x

EPSS Score

Percentile: 8%

Vendor	Product	Version
canonical	ubuntu_linux	16.04
canonical	ubuntu_linux	18.04
canonical	ubuntu_linux	20.04
canonical	ubuntu_linux	20.10

𝑥

= Vulnerable software versions

Debian Releases

Debian Product

Codename

pulseaudio

bullseye	14.2-2 fixed
bookworm	16.1+dfsg1-2 fixed
sid	16.1+dfsg1-5.1 fixed
trixie	16.1+dfsg1-5.1 fixed

Ubuntu Releases

Ubuntu Product

Codename

pulseaudio

groovy	Fixed 1:13.99.2-1ubuntu2.1 released
focal	Fixed 1:13.99.1-1ubuntu3.8 released
bionic	Fixed 1:11.1-1ubuntu7.11 released
xenial	Fixed 1:8.0-0ubuntu3.15 released
trusty	dne

Known Exploits!

Common Weakness Enumeration

CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
The program contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently.

References

https://launchpad.net/bugs/1895928

https://ubuntu.com/USN-4640-1

https://launchpad.net/bugs/1895928

https://ubuntu.com/USN-4640-1