Support Support Downloads Knowledge Base Juniper Support Portal Community

Knowledge Base

Search our Knowledge Base sites to find answers to your questions.

Ask All Knowledge Base Sites All Knowledge Base Sites JunosE Defect (KA)Knowledge BaseSecurity AdvisoriesTechnical BulletinsTechnotes Sign in to display secure content and recently viewed articles

2021-04 Security Bulletin: Junos OS: SRX Series: A remote attacker may be able to cause a PFE buffer overflow to arbitrarily remotely execute code or commands on the target device with UTM enabled. (CVE-2021-0249)



Article ID: JSA11142 SECURITY_ADVISORIES Last Updated: 14 Apr 2021Version: 1.0
Product Affected:
This issue affects Junos OS 15.1X49, 17.4, 18.1, 18.2, 18.3, 18.4, 19.1, 19.2. Affected platforms: SRX Series.

On SRX Series devices configured with UTM services a buffer overflow vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS may allow an attacker to arbitrarily execute code or commands on the target to take over or otherwise impact the device by sending crafted packets to or through the device.

This issue affects:

Juniper Networks Junos OS on SRX Series:

  • 15.1X49 versions prior to 15.1X49-D190;
  • 17.4 versions prior to 17.4R2-S9;
  • 17.4R3 and later versions prior to 18.1R3-S9;
  • 18.2 versions prior to 18.2R3-S1;
  • 18.3 versions prior to 18.3R2-S3, 18.3R3;
  • 18.4 versions prior to 18.4R2-S3, 18.4R3;
  • 19.1 versions prior to 19.1R1-S4, 19.1R2;
  • 19.2 versions prior to 19.2R1-S1, 19.2R2.

An indicator of compromise can be the following text in the UTM log:


The following minimal configuration is required to be potentially exposed to this issue:

[security utm]

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was found during internal product security testing or research.

This issue has been assigned CVE-2021-0249.


The following software releases have been updated to resolve this specific issue: 15.1X49-D190, 17.4R2-S9, 18.1R3-S9, 18.2R3-S1, 18.3R2-S3, 18.3R3, 18.4R2-S3, 18.4R3, 19.1R1-S4, 19.1R2, 19.2R1-S1, 19.2R2, 19.3R1, and all subsequent releases.

This issue is being tracked as 1441366.

There are no available workarounds for this issue other than disabling UTM services.
Software releases or updates are available for download at
Modification History:
2021-04-14: Initial Publication.
CVSS Score:
8.1 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H)
Severity Level:
Severity Assessment:
Information for how Juniper Networks uses CVSS can be found at KB 16446 "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."

Related Links

Comment on this article > Affected Products Browse the Knowledge Base for more articles related to these product categories. Select a category to begin.

Getting Up and Running with Junos

Getting Up and Running with Junos Security Alerts and Vulnerabilities Product Alerts and Software Release Notices Problem Report (PR) Search Tool EOL Notices and Bulletins JTAC User Guide Customer Care User Guide Pathfinder SRX High Availability Configurator SRX VPN Configurator Training Courses and Videos End User Licence Agreement Global Search