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2021-04 Security Bulletin: Junos OS: ACX500 Series, ACX4000 Series: Denial of Service due to FFEB crash while processing high rate of specific packets. (CVE-2021-0233)



Article ID: JSA11128 SECURITY_ADVISORIES Last Updated: 14 Apr 2021Version: 1.0
Product Affected:
This issue affects Junos OS 17.4. Affected platforms: ACX4000 Series, ACX500 Series.

A vulnerability in Juniper Networks Junos OS ACX500 Series, ACX4000 Series, may allow an attacker to cause a Denial of Service (DoS) by sending a high rate of specific packets to the device, resulting in a Forwarding Engine Board (FFEB) crash.

Continued receipt of these packets will sustain the Denial of Service (DoS) condition.

This issue affects Juniper Networks Junos OS on ACX500 Series, ACX4000 Series:

  • 17.4 versions prior to 17.4R3-S2.

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-2021-0233.


The following software releases have been updated to resolve this specific issue: 17.4R3-S2, and all subsequent releases.

This issue is being tracked as 1465802.


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:
7.5 (CVSS:3.1/AV:N/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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