CVE-2016-9937 Denial of service in n/a

High 7.5 Published 12 Dec 2016 Updated 6 Aug 2024

Unauthenticated remote attackers can crash Asterisk by sending malformed SDP offers with Opus codec parameters, causing a denial of service.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2016-9937?

CVE-2016-9937 is a high-severity denial of service vulnerability in Digium Asterisk, published on 12 Dec 2016. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

An issue was discovered in Asterisk Open Source 13.12.x and 13.13.x before 13.13.1 and 14.x before 14.2.1. If an SDP offer or answer is received with the Opus codec and with the format parameters separated using a space the code responsible for parsing will recursively call itself until it crashes. This occurs as the code does not properly handle spaces separating the parameters. This does NOT require the endpoint to have Opus configured in Asterisk. This also does not require the endpoint to be authenticated. If guest is enabled for chan_sip or anonymous in chan_pjsip an SDP offer or answer is still processed and the crash occurs.

Weakness: CWE-119

Which versions are affected by CVE-2016-9937?

It affects 1 product.

Products include Digium Asterisk.

How do I fix CVE-2016-9937?

No fix has been published for CVE-2016-9937 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2016-9937 being exploited?

There is no known exploitation of CVE-2016-9937 in the wild and no public exploit code.

All Digium Asterisk vulnerabilities

Sources

Also known as GHSA-6qm8-8j44-j9h2.