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CVE-2021-0263

5.9 · MEDIUM

A Data Processing vulnerability in the Multi-Service process (multi-svcs) on the FPC of Juniper Networks Junos OS on the PTX Series routers may lead to the process becoming unresponsive, ultimately…

Published Apr 22, 2021CWE-19EPSS 0.92%

Overview

CVE-2021-0263 is a medium-severity vulnerability. It was published on April 22, 2021 and has a CVSS 3.1 base score of 5.9 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.9, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

A Data Processing vulnerability in the Multi-Service process (multi-svcs) on the FPC of Juniper Networks Junos OS on the PTX Series routers may lead to the process becoming unresponsive, ultimately affecting traffic forwarding, allowing an attacker to cause a Denial of Service (DoS) condition . The Multi-Service Process running on the FPC is responsible for handling sampling-related operations when a J-Flow configuration is activated. This can occur during periods of heavy route churn, causing the Multi-Service Process to stop processing updates, without consuming any further updates from kernel. This back pressure towards the kernel affects further dynamic updates from other processes in the system, including RPD, causing a KRT-STUCK condition and traffic forwarding issues. An administrator can monitor the following command to check if there is the KRT queue is stuck: user@device > show krt state ... Number of async queue entries: 65007 <--- this value keep on increasing. The followin

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.

References

Refkb.juniper.net/JSA11154Refwww.juniper.net/documentation/en_US/junos/topics/example/flowmonitoring-active-sampling-instance-example.htmlRefkb.juniper.net/JSA11154Refwww.juniper.net/documentation/en_US/junos/topics/example/flowmonitoring-active-sampling-instance-example.html

How CyberStrike helps

Frequently asked questions

What is CVE-2021-0263?

CVE-2021-0263 is a medium-severity vulnerability. It was published on April 22, 2021 and has a CVSS 3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2021-0263?

This vulnerability has a CVSS 3.1 base score of 5.9, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-0263?

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-2021-0263?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-0263 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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