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.

This issue requires that SNMPv3 be configured. For example:

[snmp engine-id use-default-ip-address]
[snmp v3 usm local-engine user <username> authentication-<method> ...]
[snmp v3 vacm security-to-group security-model usm security-name <name> group <group>]
[snmp v3 vacm access group <group> default-context-prefix security-model usm security-level <level> ...]

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was seen during production usage.

This issue has been assigned CVE-2026-33799.

The following software releases have been updated to resolve this specific issue: Junos OS: 21.2R3-S8, 21.4R3-S7, 22.1R3-S6, 22.2R3-S4, 22.3R3-S3, 22.4R3-S2, 23.2R2, 23.4R2, 24.2R1, and all subsequent releases.
Junos OS Evolved: 21.2R3-S8-EVO, 21.4R3-S7-EVO, 22.2R3-S4-EVO, 22.3R3-S3-EVO, 23.2R2-EVO, 23.4R2-EVO, 24.2R1-EVO, and all subsequent releases.

This issue is being tracked as 1769065 which is visible on the Customer Support website.

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

There are no known workarounds for this issue.

To reduce the risk of malicious exploitation, use access lists or firewall filters to limit access to the device via SNMPv3 only from trusted hosts.

2026-07-08: Initial Publication

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team