CVE-2023-44181: Junos OS: QFX5k: l2 loop in the overlay impacts the stability in a EVPN/VXLAN environment

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-10-13 · updated 2026-06-17
Weakness: CWE-835

Description

An Improperly Implemented Security Check for Standard vulnerability in storm control of Juniper Networks Junos OS QFX5k devices allows packets to be punted to ARP queue causing a l2 loop resulting in a DDOS violations and DDOS syslog. This issue is triggered when Storm control is enabled and ICMPv6 packets are present on device. This issue affects Juniper Networks: Junos OS * All versions prior to 20.2R3-S6 on QFX5k; * 20.3 versions prior to 20.3R3-S5 on QFX5k; * 20.4 versions prior to 20.4R3-S5 on QFX5k; * 21.1 versions prior to 21.1R3-S4 on QFX5k; * 21.2 versions prior to 21.2R3-S3 on QFX5k; * 21.3 versions prior to 21.3R3-S2 on QFX5k; * 21.4 versions prior to 21.4R3 on QFX5k; * 22.1 versions prior to 22.1R3 on QFX5k; * 22.2 versions prior to 22.2R2 on QFX5k.

Affected products

Juniper Junos OS: before 20.2; 20.2, 20.2-r1, 20.2-r1-s1, 20.2-r1-s2, 20.2-r1-s3, 20.2-r2 (+77) — fixed in 20.2

How to fix

Upgrade to a fixed version: Juniper Junos OS 20.2. Check the vendor advisory for mitigations.

References

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