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CVE-2021-0216

6.5 · MEDIUM

A vulnerability in Juniper Networks Junos OS running on the ACX5448 and ACX710 platforms may cause BFD sessions to flap when a high rate of transit ARP packets are received.

Published Apr 22, 2021EPSS 0.40%

Overview

CVE-2021-0216 is a medium-severity vulnerability. It was published on April 22, 2021 and has a CVSS 3.1 base score of 6.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

Technical description

A vulnerability in Juniper Networks Junos OS running on the ACX5448 and ACX710 platforms may cause BFD sessions to flap when a high rate of transit ARP packets are received. This, in turn, may impact routing protocols and network stability, leading to a Denial of Service (DoS) condition. When a high rate of transit ARP packets are exceptioned to the CPU and BFD flaps, the following log messages may be seen: bfdd[15864]: BFDD_STATE_UP_TO_DOWN: BFD Session 192.168.14.3 (IFL 232) state Up -> Down LD/RD(17/19) Up time:11:38:17 Local diag: CtlExpire Remote diag: None Reason: Detect Timer Expiry. bfdd[15864]: BFDD_TRAP_SHOP_STATE_DOWN: local discriminator: 17, new state: down, interface: irb.998, peer addr: 192.168.14.3 rpd[15839]: RPD_ISIS_ADJDOWN: IS-IS lost L2 adjacency to peer on irb.998, reason: BFD Session Down bfdd[15864]: BFDD_TRAP_SHOP_STATE_UP: local discriminator: 17, new state: up, interface: irb.998, peer addr: 192.168.14.3 This issue only affects the ACX5448 Series and ACX710 S

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Frequently asked questions

What is CVE-2021-0216?

CVE-2021-0216 is a medium-severity vulnerability. It was published on April 22, 2021 and has a CVSS 3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2021-0216?

This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-0216?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-0216?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-0216 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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