CVE-2026-33799: Juniper Junos

Medium severity, CVSS 4.3. EPSS: 0.4% chance of exploitation in the next 30 days.

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.

Affected products

• Juniper Junos: before 21.2 (fixed in 21.2); version 21.2 only; version 21.4 only; version 22.1 only; version 22.2 only; version 22.3 only; …
• Juniper Junos OS Evolved: before 21.2 (fixed in 21.2); version 21.2 only; version 21.4 only; version 22.1 only; version 22.2 only; version 22.3 only; …

Published 2026-07-09. Last modified 2026-07-13.