CVE-2021-0217

Junos OS: EX Series and QFX Series: Memory leak issue processing specific DHCP packets

HIGH

7.4

CVSS Score

Published: January 15, 2021 at 05:35 PM UTC

Updated: June 17, 2026 at 03:29 AM UTC

21 products affected across 2 vendorsJunosQfx5200Qfx5110

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Severity

HIGH7.4

Exploit prediction

EPSS 0.7%

Description

A vulnerability in processing of certain DHCP packets from adjacent clients on EX Series and QFX Series switches running Juniper Networks Junos OS with DHCP local/relay server configured may lead to exhaustion of DMA memory causing a Denial of Service (DoS). Over time, exploitation of this vulnerability may cause traffic to stop being forwarded, or to crashing of the fxpc process. When Packet DMA heap utilization reaches 99%, the system will become unstable. Packet DMA heap utilization can be monitored through the following command: user@junos# request pfe execute target fpc0 timeout 30 command "show heap" ID Base Total(b) Free(b) Used(b) % Name -- ---------- ----------- ----------- ----------- --- ----------- 0 213301a8 536870488 387228840 149641648 27 Kernel 1 91800000 8388608 3735120 4653488 55 DMA 2 92000000 75497472 74452192 1045280 1 PKT DMA DESC 3 d330000 335544320 257091400 78452920 23 Bcm_sdk 4 96800000 184549376 2408 184546968 99 Packet DMA <--- 5 903fffe0 20971504 20971504 0 0 Blob An indication of the issue occurring may be observed through the following log messages: Dec 10 08:07:00.124 2020 hostname fpc0 brcm_pkt_buf_alloc:523 (buf alloc) failed allocating packet buffer Dec 10 08:07:00.126 2020 hostname fpc0 (buf alloc) failed allocating packet buffer Dec 10 08:07:00.128 2020 hostname fpc0 brcm_pkt_buf_alloc:523 (buf alloc) failed allocating packet buffer Dec 10 08:07:00.130 2020 hostnameC fpc0 (buf alloc) failed allocating packet buffer This issue affects Juniper Networks Junos OS on EX Series and QFX Series: 17.4R3 versions prior to 17.4R3-S3; 18.1R3 versions between 18.1R3-S6 and 18.1R3-S11; 18.2R3 versions prior to 18.2R3-S6; 18.3R3 versions prior to 18.3R3-S4; 18.4R2 versions prior to 18.4R2-S5; 18.4R3 versions prior to 18.4R3-S6; 19.1 versions between 19.1R2 and 19.1R3-S3; 19.2 versions prior to 19.2R3-S1; 19.3 versions prior to 19.3R2-S5, 19.3R3; 19.4 versions prior to 19.4R2-S2, 19.4R3; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R1-S2, 20.2R2. Junos OS versions prior to 17.4R3 are unaffected by this vulnerability.

Affected

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

Junos · Juniper Networks

95%

17.4 ≤ v < 17.4R3-S318.1R3-S6 ≤ v < 18.1*18.2R3 ≤ v < 18.2*18.3R3 ≤ v < 18.3*18.4R2 ≤ v < 18.4*19.1R2 ≤ v < 19.1*19.2 ≤ v < 19.2R3-S119.3 ≤ v < 19.3R2-S5, 19.3R319.4 ≤ v < 19.4R2-S2, 19.4R320.1 ≤ v < 20.1R220.2 ≤ v < 20.2R1-S2, 20.2R217.4 17.4 r3 17.4 r3-s1 17.4 r3-s2 18.1 r3-s10 18.1 r3-s7 18.1 r3-s8 18.1 r3-s9 18.1R3-S6 18.2 r3 18.2 r3-s1 18.2 r3-s2 18.2 r3-s3 18.2 r3-s4 18.2 r3-s5 18.2R3 18.3 r3 18.3 r3-s1 18.3 r3-s2 18.3 r3-s3 18.3R3 18.4 r2 18.4 r2-s1 18.4 r2-s2 18.4 r2-s3 18.4 r2-s4 18.4R2 19.1 r2-s1 19.1 r3 19.1 r3-s1 19.1 r3-s2 19.1R2 19.2 19.2 r1 19.2 r1-s1 19.2 r1-s2 19.2 r1-s3 19.2 r1-s4 19.2 r2 19.2 r3 19.3 19.3 r1 19.3 r1-s1 19.3 r2 19.3 r2-s1 19.3 r2-s2 19.3 r2-s3 19.3 r2-s4 19.4 19.4 r1 19.4 r1-s1 19.4 r1-s2 19.4 r2 19.4 r2-s1 20.1 20.1 r1 20.1 r1-s1 20.1 r1-s2 20.1 r1-s3 20.2 20.2 r1 20.2 r1-s1

Vendor states this is fixed in 17.4R3 (unaffected)

Affected range stops below 17.4R3-S3, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.1*, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.2*, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.3*, so it looks safe — our inference, not a vendor statement

Affected range stops below 18.4*, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.1*, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.2R3-S1, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.3R2-S5, 19.3R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 19.4R2-S2, 19.4R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.1R2, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.2R1-S2, 20.2R2, so it looks safe — our inference, not a vendor statement

juniper-ex2300 (environment) · juniper-ex2300-c (environment) · juniper-ex2300m (environment) · juniper-ex3400 (environment) · juniper-ex4300 (environment) · juniper-ex4300m (environment) · juniper-ex4600 (environment) · juniper-ex4650 (environment) · juniper-ex9200 (environment) · juniper-ex9250 (environment) · juniper-qfx10002 (environment) · juniper-qfx10008 (environment) · juniper-qfx10016 (environment) · juniper-qfx5100 (environment) · juniper-qfx5110 (environment) · juniper-qfx5120 (environment) · juniper-qfx5130 (environment) · juniper-qfx5200 (environment) · juniper-qfx5210 (environment) · juniper-qfx5220 (environment)

Ex2300 · Juniperdevice

80%

All versions

Ex2300-C · Juniperdevice

80%

All versions

Ex2300M · Juniperdevice

80%

All versions

Ex3400 · Juniperdevice

80%

All versions