CVE-2020-28327

Public Exploit

Description

A res_pjsip_session crash was discovered in Asterisk Open Source 13.x before 13.37.1, 16.x before 16.14.1, 17.x before 17.8.1, and 18.x before 18.0.1. and Certified Asterisk before 16.8-cert5. Upon receiving a new SIP Invite, Asterisk did not return the created dialog locked or referenced. This caused a gap between the creation of the dialog object, and its next use by the thread that created it. Depending on some off-nominal circumstances and timing, it was possible for another thread to free said dialog in this gap. Asterisk could then crash when the dialog object, or any of its dependent objects, were dereferenced or accessed next by the initial-creation thread. Note, however, that this crash can only occur when using a connection-oriented protocol (e.g., TCP or TLS, but not UDP) for SIP transport. Also, the remote client must be authenticated, or Asterisk must be configured for anonymous calling.

Category

5.3
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 2.76% Top 15%
Vendor Advisory asterisk.org Vendor Advisory asterisk.org
Affected: n/a n/a
Published at:
Updated at:

References

Link Tags
http://downloads.asterisk.org/pub/security/AST-2020-001.html patch vendor advisory
https://issues.asterisk.org/jira/browse/ASTERISK-29057 issue tracking exploit vendor advisory

Frequently Asked Questions

What is the severity of CVE-2020-28327?
CVE-2020-28327 has been scored as a medium severity vulnerability.
How to fix CVE-2020-28327?
To fix CVE-2020-28327, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2020-28327 being actively exploited in the wild?
It is possible that CVE-2020-28327 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~3% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
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