CVE-2021-0272: A kernel memory leak in QFX10002-32Q, QFX10002-60C, QFX10002-72Q, QFX10008, QFX10016 devices Flexible PIC Concentrators (FPCs) on Juniper Networks Jun...

Description

A kernel memory leak in QFX10002-32Q, QFX10002-60C, QFX10002-72Q, QFX10008, QFX10016 devices Flexible PIC Concentrators (FPCs) on Juniper Networks Junos OS allows an attacker to send genuine packets destined to the device to cause a Denial of Service (DoS) to the device. On QFX10002-32Q, QFX10002-60C, QFX10002-72Q devices the device will crash and restart. On QFX10008, QFX10016 devices, depending on the number of FPCs involved in an attack, one more more FPCs may crash and traffic through the device may be degraded in other ways, until the attack traffic stops. A reboot is required to restore service and clear the kernel memory. Continued receipt and processing of these genuine packets will create a sustained Denial of Service (DoS) condition. On QFX10008, QFX10016 devices, an indicator of compromise may be the existence of DCPFE core files. You can also monitor PFE memory utilization for incremental growth: user@qfx-RE:0% cprod -A fpc0 -c "show heap 0" | grep -i ke 0 3788a1b0 3221225048 2417120656 804104392 24 Kernel user@qfx-RE:0% cprod -A fpc0 -c "show heap 0" | grep -i ke 0 3788a1b0 3221225048 2332332200 888892848 27 Kernel This issue affects: Juniper Networks Junos OS on QFX10002-32Q, QFX10002-60C, QFX10002-72Q, QFX10008, QFX10016: 16.1 versions 16.1R1 and above prior to 17.3 versions prior to 17.3R3-S9; 17.4 versions prior to 17.4R3-S2; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S5; 18.3 versions prior to 18.3R3-S3; 18.4 versions prior to 18.4R2-S5, 18.4R3-S4; 19.1 versions prior to 19.1R3-S2; 19.2 versions prior to 19.2R3; 19.3 versions prior to 19.3R3; 19.4 versions prior to 19.4R3; 20.1 versions prior to 20.1R2. This issue does not affect releases prior to Junos OS 16.1R1. This issue does not affect EX Series devices. This issue does not affect Junos OS Evolved.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.42%

33.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Juniper	Junos	16.1	R1
Juniper	Junos	16.2	—
Juniper	Junos	17.1	—
Juniper	Junos	17.2	—
Juniper	Junos	17.3	—
Juniper	Junos	17.4	—
Juniper	Junos	18.1	—
Juniper	Junos	18.2	—
Juniper	Junos	18.3	—
Juniper	Junos	18.4	—
Juniper	Junos	19.1	—
Juniper	Junos	19.2	—
Juniper	Junos	19.3	—
Juniper	Junos	19.4	R1
Juniper	Junos	20.1	R1

References

https://kb.juniper.net/JSA11163Vendor Advisory
https://kb.juniper.net/KB32854Vendor Advisory
https://kb.juniper.net/JSA11163Vendor Advisory
https://kb.juniper.net/KB32854Vendor Advisory

Timeline

Published: Apr 22, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-0272?

A kernel memory leak in QFX10002-32Q, QFX10002-60C, QFX10002-72Q, QFX10008, QFX10016 devices Flexible PIC Concentrators (FPCs) on Juniper Networks Junos OS allows an attacker to send genuine packets destined to the device to cause a Denial of Service (DoS) to the device. On QFX10002-32Q, QFX10002-60C, QFX10002-72Q devices the device will crash and restart. On QFX10008, QFX10016 devices, depending on the number of FPCs involved in an attack, one more more FPCs may crash and traffic through the device may be degraded in other ways, until the attack traffic stops. A reboot is required to restore service and clear the kernel memory. Continued receipt and processing of these genuine packets will create a sustained Denial of Service (DoS) condition. On QFX10008, QFX10016 devices, an indicator of compromise may be the existence of DCPFE core files. You can also monitor PFE memory utilization for incremental growth: user@qfx-RE:0% cprod -A fpc0 -c "show heap 0" | grep -i ke 0 3788a1b0 3221225048 2417120656 804104392 24 Kernel user@qfx-RE:0% cprod -A fpc0 -c "show heap 0" | grep -i ke 0 3788a1b0 3221225048 2332332200 888892848 27 Kernel This issue affects: Juniper Networks Junos OS on QFX10002-32Q, QFX10002-60C, QFX10002-72Q, QFX10008, QFX10016: 16.1 versions 16.1R1 and above prior to 17.3 versions prior to 17.3R3-S9; 17.4 versions prior to 17.4R3-S2; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S5; 18.3 versions prior to 18.3R3-S3; 18.4 versions prior to 18.4R2-S5, 18.4R3-S4; 19.1 versions prior to 19.1R3-S2; 19.2 versions prior to 19.2R3; 19.3 versions prior to 19.3R3; 19.4 versions prior to 19.4R3; 20.1 versions prior to 20.1R2. This issue does not affect releases prior to Junos OS 16.1R1. This issue does not affect EX Series devices. This issue does not affect Junos OS Evolved.

How severe is CVE-2021-0272?

CVE-2021-0272 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.42% probability of exploitation in the next 30 days.

How do I fix CVE-2021-0272?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.