Libsixel CVE-2019-20023 Memory Leak Denial of Service Vulnerability

ID SMNTC-111335
Type symantec
Reporter Symantec Security Response
Modified 2019-12-20T00:00:00



Libsixel is prone to a denial-of-service vulnerability. An attacker can exploit this issue to crash the application; denying service to legitimate users. Libsixel versions through 1.8.4 are vulnerable.

Technologies Affected

  • Libsixel Libsixel 1.0.0
  • Libsixel Libsixel 1.1.0
  • Libsixel Libsixel 1.2.0
  • Libsixel Libsixel 1.3.0
  • Libsixel Libsixel 1.4.0
  • Libsixel Libsixel 1.5.0
  • Libsixel Libsixel 1.5.1
  • Libsixel Libsixel 1.5.2
  • Libsixel Libsixel 1.5.3
  • Libsixel Libsixel 1.6.0
  • Libsixel Libsixel 1.6.1
  • Libsixel Libsixel 1.7.1
  • Libsixel Libsixel 1.7.2
  • Libsixel Libsixel 1.7.3
  • Libsixel Libsixel 1.8.0
  • Libsixel Libsixel 1.8.1
  • Libsixel Libsixel 1.8.2
  • Libsixel Libsixel 1.8.3
  • Libsixel Libsixel 1.8.4


Run all software as a nonprivileged user with minimal access rights.
To reduce the impact of latent vulnerabilities, run the application with the minimal amount of privileges required for functionality.

Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Deploy NIDS to monitor network traffic for signs of anomalous or suspicious activity. This includes but is not limited to requests that include NOP sleds and unexplained incoming and outgoing traffic. This may indicate exploit attempts or activity that results from a successful exploit.

Implement multiple redundant layers of security.
Various memory-protection schemes (such as nonexecutable and randomly mapped memory segments) may hinder an attacker's ability to exploit this vulnerability to execute arbitrary code.

Updates are available. Please see the references or vendor advisory for more information.