CVE-2026-33799

An Out-of-bounds Write vulnerability in the SNMP daemon (snmpd) of Juniper Networks Junos OS and Junos OS Evolved allows an authenticated network-based attacker sending specific valid SNMPv3 queries to trigger a memory leak. Over time, continuous receipt of these queries will result in snmpd process memory exhaustion, resulting in a process crash and restart, impacting the ability to monitor the system via SNMP.

Memory usage can be monitored using the following command:

user@device> show system processes extensive | match snmpd

This issue affects:

Junos OS:

• all versions before 21.2R3-S8;
• from 21.4 before 21.4R3-S7;
• from 22.1 before 22.1R3-S6;
• from 22.2 before 22.2R3-S4;
• from 22.3 before 22.3R3-S3;
• from 22.4 before 22.4R3-S2;
• from 23.2 before 23.2R2;
• from 23.4 before 23.4R2.

Junos OS Evolved:

• all versions before 21.2R3-S8-EVO;
• from 21.4 before 21.4R3-S7-EVO;
• all versions of 22.1-EVO,
• from 22.2 before 22.2R3-S4-EVO;
• from 22.3 before 22.3R3-S3-EVO;
• all versions of 22.4-EVO,
• from 23.2 before 23.2R2-EVO;
• from 23.4 before 23.4R2-EVO.