CVE-2026-33799

/// Technical description

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;

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References