CVE-2021-0258

Junos OS: Kernel panic upon receipt of specific TCPv6 packet on management interface

Description

A vulnerability in the forwarding of transit TCPv6 packets received on the Ethernet management interface of Juniper Networks Junos OS allows an attacker to trigger a kernel panic, leading to a Denial of Service (DoS). Continued receipt and processing of these transit packets will create a sustained Denial of Service (DoS) condition. This issue only occurs when TCPv6 packets are routed through the management interface. Other transit traffic, and traffic destined to the management interface, are unaffected by this vulnerability. This issue was introduced as part of a TCP Parallelization feature added in Junos OS 17.2, and affects systems with concurrent network stack enabled. This feature is enabled by default, but can be disabled (see WORKAROUND section below). This issue affects Juniper Networks Junos OS: 17.2 versions prior to 17.2R3-S4; 17.3 versions prior to 17.3R3-S9; 17.4 versions prior to 17.4R2-S11, 17.4R3-S2; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S5; 18.3 versions prior to 18.3R2-S4, 18.3R3-S3; 18.4 versions prior to 18.4R2-S5, 18.4R3-S4; 19.1 versions prior to 19.1R2-S2, 19.1R3; 19.2 versions prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S4, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2. This issue does not affect Juniper Networks Junos OS versions prior to 17.2R1.

Remediation

Solution:

  • The following software releases have been updated to resolve this specific issue: Junos OS 17.2R3-S4, 17.3R3-S9, 17.4R2-S11, 17.4R3-S2, 18.1R3-S11, 18.2R3-S5, 18.3R2-S4, 18.3R3-S3, 18.4R2-S5, 18.4R3-S4, 19.1R2-S2, 19.1R3, 19.2R1-S5, 19.2R2, 19.3R2-S4, 19.3R3, 19.4R1-S3, 19.4R2, 20.1R1, and all subsequent releases.

Workaround:

  • Disable TCP Parallelization: set system kernel-smp-features disable-concurrent-network-stack

Category

5.9
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.20%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS
Published at:
Updated at:

References

Link Tags
https://kb.juniper.net/JSA11149 vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-0258?
CVE-2021-0258 has been scored as a medium severity vulnerability.
How to fix CVE-2021-0258?
To fix CVE-2021-0258: The following software releases have been updated to resolve this specific issue: Junos OS 17.2R3-S4, 17.3R3-S9, 17.4R2-S11, 17.4R3-S2, 18.1R3-S11, 18.2R3-S5, 18.3R2-S4, 18.3R3-S3, 18.4R2-S5, 18.4R3-S4, 19.1R2-S2, 19.1R3, 19.2R1-S5, 19.2R2, 19.3R2-S4, 19.3R3, 19.4R1-S3, 19.4R2, 20.1R1, and all subsequent releases.
Is CVE-2021-0258 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-0258 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-2021-0258?
CVE-2021-0258 affects Juniper Networks Junos OS.
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