CVE-2021-0238

Junos OS: MX Series: Executing CLI command repetitively may cause the system to run out of disk space

Description

When a MX Series is configured as a Broadband Network Gateway (BNG) based on Layer 2 Tunneling Protocol (L2TP), executing certain CLI command may cause the system to run out of disk space, excessive disk usage may cause other complications. An administrator can use the following CLI command to monitor the available disk space: user@device> show system storage Filesystem Size Used Avail Capacity Mounted on /dev/gpt/junos 19G 18G 147M 99% /.mount <<<<< running out of space tmpfs 21G 16K 21G 0% /.mount/tmp tmpfs 5.3G 1.7M 5.3G 0% /.mount/mfs This issue affects Juniper Networks Junos OS on MX Series: 17.3R1 and later versions prior to 17.4R3-S5, 18.1 versions prior to 18.1R3-S13, 18.2 versions prior to 18.2R3-S7; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R3-S7; 19.1 versions prior to 19.1R3-S4; 19.2 versions prior to 19.2R1-S6, 19.2R3-S2; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R2-S4, 19.4R3-S2; 20.1 versions prior to 20.1R3; 20.2 versions prior to 20.2R2-S3, 20.2R3; 20.3 versions prior to 20.3R2; 20.4 versions prior to 20.4R1-S1, 20.4R2; This issue does not affect Juniper Networks Junos OS versions prior to 17.3R1.

Remediation

Solution:

  • The following software releases have been updated to resolve this specific issue: 17.4R3-S5, 18.1R3-S13, 18.2R3-S7, 18.3R3-S4, 18.4R3-S7, 19.1R3-S4, 19.2R1-S6, 19.2R3-S2, 19.3R3-S2, 19.4R2-S4, 19.4R3-S2, 20.1R3, 20.2R2-S3, 20.2R3, 20.3R2, 20.4R1-S1, 20.4R2, 21.1R1, and all subsequent releases. If impacted, issue is recoverable after restarting the jl2tpd daemon: user@device> restart l2tp-universal-edge

Workaround:

  • There are no viable workarounds for this issue. To reduce the risk of exploitation of this issue, use access lists or firewall filters to limit access to the CLI only trusted administrative networks, hosts and users.

Category

5.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.04%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS
Affected: Juniper Networks Junos OS
Published at:
Updated at:

References

Link Tags
https://kb.juniper.net/JSA11133 vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-0238?
CVE-2021-0238 has been scored as a medium severity vulnerability.
How to fix CVE-2021-0238?
To fix CVE-2021-0238: The following software releases have been updated to resolve this specific issue: 17.4R3-S5, 18.1R3-S13, 18.2R3-S7, 18.3R3-S4, 18.4R3-S7, 19.1R3-S4, 19.2R1-S6, 19.2R3-S2, 19.3R3-S2, 19.4R2-S4, 19.4R3-S2, 20.1R3, 20.2R2-S3, 20.2R3, 20.3R2, 20.4R1-S1, 20.4R2, 21.1R1, and all subsequent releases. If impacted, issue is recoverable after restarting the jl2tpd daemon: user@device> restart l2tp-universal-edge
Is CVE-2021-0238 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-0238 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-2021-0238?
CVE-2021-0238 affects Juniper Networks Junos OS, Juniper Networks Junos OS.
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