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
An attacker can cause a routing process crash and sustained denial of service by flapping an ISIS link in specific SR-ISIS/MPLS configurations.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2021-0287?
CVE-2021-0287 is a medium-severity denial of service vulnerability in Juniper Junos, published on 15 Jul 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-754
Which versions are affected by CVE-2021-0287?
It affects 2 products.
Products include Juniper Junos, Juniper Junos Os Evolved.
How do I fix CVE-2021-0287?
No fix has been published for CVE-2021-0287 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-0287 being exploited?
There is no known exploitation of CVE-2021-0287 in the wild and no public exploit code.
Other vulnerabilities in Juniper Junos
- CVE-2023-36845 Juniper Junos OS EX Series and SRX Series PHP External Variable Modification
- CVE-2020-1631 Juniper Junos OS Path Traversal
- CVE-2025-21590 Juniper Junos OS Improper Isolation or Compartmentalization
- CVE-2023-36851 Juniper Junos OS SRX Series Missing Authentication for Critical Function
- CVE-2023-36844 Juniper Junos OS EX Series PHP External Variable Modification
Sources
Also known as GHSA-rr23-qf6q-44wq.