CVE-2021-0292

Junos OS Evolved: Memory leak in arpd or ndp processes can lead to Denial of Service (DoS)

MEDIUM
6.5
CVSS Score
Published: July 15, 2021 at 08:01 PM UTC
Updated: June 17, 2026 at 03:29 AM UTC
2 products affected across 2 vendorsJunos OS EvolvedJunos OS Evolved

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.4%

Description

An Uncontrolled Resource Consumption vulnerability in the ARP daemon (arpd) and Network Discovery Protocol (ndp) process of Juniper Networks Junos OS Evolved allows a malicious attacker on the local network to consume memory resources, ultimately resulting in a Denial of Service (DoS) condition. Link-layer functions such as IPv4 and/or IPv6 address resolution may be impacted, leading to traffic loss. The processes do not recover on their own and must be manually restarted. Changes in memory usage can be monitored using the following shell commands (header shown for clarity): user@router:/var/log# ps aux | grep arpd USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 31418 59.0 0.7 *5702564* 247952 ? xxx /usr/sbin/arpd --app-name arpd -I object_select --shared-objects-mode 3 user@router:/var/log# ps aux | grep arpd USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 31418 49.1 1.0 *5813156* 351184 ? xxx /usr/sbin/arpd --app-name arpd -I object_select --shared-objects-mode 3 Memory usage can be monitored for the ndp process in a similar fashion: user@router:/var/log# ps aux | grep ndp USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 14935 0.0 0.1 *5614052* 27256 ? Ssl Jun15 0:17 /usr/sbin/ndp -I no_tab_chk,object_select --app-name ndp --shared-obje user@router:/var/log# ps aux | grep ndp USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 14935 0.0 0.1 *5725164* 27256 ? Ssl Jun15 0:17 /usr/sbin/ndp -I no_tab_chk,object_select --app-name ndp --shared-obje This issue affects Juniper Networks Junos OS Evolved: 19.4 versions prior to 19.4R2-S3-EVO; 20.1 versions prior to 20.1R2-S4-EVO; all versions of 20.2-EVO. This issue does not affect Juniper Networks Junos OS Evolved versions prior to 19.4R2-EVO.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

19.4 ≤ v < 19.4R2-S3-EVO20.1 ≤ v < 20.1R2-S4-EVO20.2R1-EVO ≤ v < 20.2*19.420.120.2R1-EVO
Vendor states this is fixed in 19.4R2-EVO (unaffected)
Affected range stops below 19.4R2-S3-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 20.1R2-S4-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 20.2*, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (1)

x_refsource_CONFIRMVendor Advisory
https://kb.juniper.net/JSA11194

CVSS

6.5MEDIUMjuniper
Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-400

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