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2021-04 Security Bulletin: Junos OS Evolved: Stateless IP firewall filter does not work as expected (CVE-2021-0225)



Article ID: JSA11120 SECURITY_ADVISORIES Last Updated: 14 Apr 2021Version: 1.0
Product Affected:
This issue affects Junos OS Evolved 19.1R1-EVO and above prior to 20.3R1-S2-EVO, 20.3R2-EVO.

An Improper Check for Unusual or Exceptional Conditions in Juniper Networks Junos OS Evolved may cause the stateless firewall filter configuration which uses the action 'policer' in certain combinations with other options to not take effect.

An administrator can use the following CLI command to see the failures with filter configuration:

user@device> show log kfirewall-agent.log | match ERROR
Jul 23 14:16:03 ERROR: filter not supported

This issue affects Juniper Networks Junos OS Evolved:

  • Versions 19.1R1-EVO and above prior to 20.3R1-S2-EVO, 20.3R2-EVO.

This issue does not affect Juniper Networks Junos OS.

The examples of the config stanza affected by this issue:

[firewall policer]
[firewall filter]

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-2021-0225.


The following software releases have been updated to resolve this specific issue: Junos OS Evolved: 20.3R1-S2-EVO, 20.3R2-EVO, 20.4R1-EVO, and all subsequent releases.

This issue is being tracked as 1528091.


There are no viable workarounds for this issue.

Software releases or updates are available for download at
Modification History:
2021-04-14: Initial Publication.
CVSS Score:
5.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N)
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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