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2021-01 Security Bulletin: Junos OS Evolved: Receipt of certain valid BGP update packets from BGP peers may cause RPD to core when using REGEX. (CVE-2021-0209)



Article ID: JSA11099 SECURITY_ADVISORIES Last Updated: 13 Jan 2021Version: 3.0
Product Affected:
This issue affects Junos OS Evolved 19.4, 20.1.

In Juniper Networks Junos OS Evolved an attacker sending certain valid BGP update packets may cause Junos OS Evolved to access an uninitialized pointer causing RPD to core leading to a Denial of Service (DoS).

Continued receipt of these types of valid BGP update packets will cause an extended Denial of Service condition.

RPD will require a restart to recover.

An indicator of compromise is to see if the file exists by issuing the command:

show system core-dumps

This issue affects:

Juniper Networks Junos OS Evolved

  • 19.4 versions prior to 19.4R2-S2-EVO;
  • 20.1 versions prior to 20.1R1-S2-EVO, 20.1R2-S1-EVO.

This issue does not affect Junos OS.

The following minimal configuration which will vary by implementation is necessary:

  • Must be running Junos OS Evolved
  • A BGP peering session is configured.
  • Regular expressions (REGEX) are being used with BGP.

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

This issue was seen during production usage.

This issue has been assigned CVE-2021-0209.


The following software releases have been updated to resolve this specific issue: Junos OS Evolved: 19.4R2-S2-EVO, 20.1R1-S2-EVO, 20.1R2-S1-EVO, 20.2R1-EVO and all subsequent releases.

This issue is being tracked as 1517128.

There are no available workarounds for this issue.
Software releases or updates are available for download at
Modification History:
2021-01-13: Initial Publication.
CVSS Score:
6.5 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/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."

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