CVE-2020-28327

MEDIUM EPSS 77.9%
Published Nov 6, 20205y ago · Modified Jun 17, 20262w ago
5.3 CVSS 3.1
Medium
Find Similar
Published Nov 6, 2020 5y ago
Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score
5.3
Exploitability
1.6
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Network
Attack Complexity High
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
77.9% percentile
Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 1

CWE-404

Affected Products 16

VendorProductVersionRange
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
digiumcertified_asterisk16.8any
sangomaasterisk*≥13.0.0  –  <13.37.1
sangomaasterisk*≥16.0.0  –  <16.14.1
sangomaasterisk*≥17.0.0  –  <17.8.1
sangomaasterisk*≥18.0.0  –  <18.0.1

References 2

  • downloads.asterisk.org http://downloads.asterisk.org/pub/security/AST-2020-001.html
    PatchVendor Advisory
  • issues.asterisk.org https://issues.asterisk.org/jira/browse/ASTERISK-29057
    ExploitIssue TrackingVendor Advisory

Remediation