CVE-2021-0299 Junos OS: Kernel crash (vmcore) upon receipt of a malformed IPv6 packet

High 7.5 Published 19 Oct 2021 Updated 16 Sep 2024

A remote attacker can cause a kernel crash and device restart by sending a malformed IPv6 packet, resulting in a sustained denial of service.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2021-0299?

CVE-2021-0299 is a high-severity denial of service vulnerability in Juniper Junos, published on 19 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

An Improper Handling of Exceptional Conditions vulnerability in the processing of a transit or directly received malformed IPv6 packet in Juniper Networks Junos OS results in a kernel crash, causing the device to restart, leading to a Denial of Service (DoS). Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue only affects systems with IPv6 configured. Devices with only IPv4 configured are not vulnerable to this issue. This issue affects Juniper Networks Junos OS: 19.4 versions prior to 19.4R3; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R1-S1, 20.2R2. This issue does not affect Juniper Networks Junos OS versions prior to 19.4R1.

Weakness: CWE-755

Which versions are affected by CVE-2021-0299?

It affects 1 product.

Products include Juniper Junos.

How do I fix CVE-2021-0299?

No fix has been published for CVE-2021-0299 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-2021-0299 being exploited?

There is no known exploitation of CVE-2021-0299 in the wild and no public exploit code.

All Juniper Junos vulnerabilities

Sources

Also known as GHSA-cfcv-4r42-7465.