CVE-2021-0287

Junos OS and Junos OS Evolved: RPD could crash in SR-ISIS/MPLS environment due to a flap of an ISIS link in the network

Description

In a Segment Routing ISIS (SR-ISIS)/MPLS environment, on Juniper Networks Junos OS and Junos OS Evolved devices, configured with ISIS Flexible Algorithm for Segment Routing and sensor-based statistics, a flap of a ISIS link in the network, can lead to a routing process daemon (RPD) crash and restart, causing a Denial of Service (DoS). Continued link flaps will create a sustained Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS: 19.4 versions prior to 19.4R1-S4, 19.4R3-S2; 20.1 versions prior to 20.1R2-S1, 20.1R3; 20.2 versions prior to 20.2R2-S2, 20.2R3; 20.3 versions prior to 20.3R2; Juniper Networks Junos OS Evolved: 20.3-EVO versions prior to 20.3R2-EVO; 20.4-EVO versions prior to 20.4R2-EVO. This issue does not affect: Juniper Networks Junos OS releases prior to 19.4R1. Juniper Networks Junos OS Evolved releases prior to 19.4R1-EVO.

Remediation

Solution:

  • The following software releases have been updated to resolve this specific issue: Junos OS: 19.4R1-S4, 19.4R3-S2, 20.1R2-S1, 20.1R3, 20.2R2-S2, 20.2R3, 20.3R2, 20.4R1, and all subsequent releases. Junos OS Evolved: 20.3R2-EVO, 20.4R2-EVO, 21.1R1-EVO, and all subsequent releases.

Workaround:

  • Disabling IS-IS Flexible Algorithm for Segment Routing or sensor-based statistics will mitigate this issue.

Category

6.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.08%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS
Affected: Juniper Networks Junos OS Evolved
Published at:
Updated at:

References

Link Tags
https://kb.juniper.net/JSA11189 vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-0287?
CVE-2021-0287 has been scored as a medium severity vulnerability.
How to fix CVE-2021-0287?
To fix CVE-2021-0287: The following software releases have been updated to resolve this specific issue: Junos OS: 19.4R1-S4, 19.4R3-S2, 20.1R2-S1, 20.1R3, 20.2R2-S2, 20.2R3, 20.3R2, 20.4R1, and all subsequent releases. Junos OS Evolved: 20.3R2-EVO, 20.4R2-EVO, 21.1R1-EVO, and all subsequent releases.
Is CVE-2021-0287 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-0287 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-0287?
CVE-2021-0287 affects Juniper Networks Junos OS, Juniper Networks Junos OS Evolved.
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