CVE-2023-44203: Junos OS: QFX5000 Series, EX2300, EX3400, EX4100, EX4400 and EX4600: Packet flooding will occur when IGMP traffic is sent to an isolated VLAN

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% 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-703

Description

An Improper Check or Handling of Exceptional Conditions vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on QFX5000 Series, EX2300, EX3400, EX4100, EX4400 and EX4600 allows a adjacent attacker to send specific traffic, which leads to packet flooding, resulting in a Denial of Service (DoS). When a specific IGMP packet is received in an isolated VLAN, it is duplicated to all other ports under the primary VLAN, which causes a flood. This issue affects QFX5000 series, EX2300, EX3400, EX4100, EX4400 and EX4600 platforms only. This issue affects Juniper Junos OS on on QFX5000 Series, EX2300, EX3400, EX4100, EX4400 and EX4600: * All versions prior to 20.4R3-S5; * 21.1 versions prior to 21.1R3-S4; * 21.2 versions prior to 21.2R3-S3; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S2; * 22.1 versions prior to 22.1R3; * 22.2 versions prior to 22.2R3; * 22.3 versions prior to 22.3R2.

Affected products

Juniper Junos OS: before 20.4; 20.4, 20.4-r1, 20.4-r1-s1, 20.4-r2, 20.4-r2-s1, 20.4-r2-s2 (+61) — fixed in 20.4

How to fix

Upgrade to a fixed version: Juniper Junos OS 20.4. Check the vendor advisory for mitigations.

References

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