CVE-2026-33799

Summary

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 Software

VendorProductVersion RangeStatus
Juniper NetworksJunos OS0 < 21.2R3-S8affected
Juniper NetworksJunos OS21.4 < 21.4R3-S7affected
Juniper NetworksJunos OS22.1 < 22.1R3-S6affected
Juniper NetworksJunos OS22.2 < 22.2R3-S4affected
Juniper NetworksJunos OS22.3 < 22.3R3-S3affected
Juniper NetworksJunos OS22.4 < 22.4R3-S2affected
Juniper NetworksJunos OS23.2 < 23.2R2affected
Juniper NetworksJunos OS23.4 < 23.4R2affected
Juniper NetworksJunos OS Evolved0 < 21.2R3-S8-EVOaffected
Juniper NetworksJunos OS Evolved21.4 < 21.4R3-S7-EVOaffected
Juniper NetworksJunos OS Evolved22.1 < 22.1*affected
Juniper NetworksJunos OS Evolved22.2 < 22.2R3-S4-EVOaffected
Juniper NetworksJunos OS Evolved22.3 < 22.3R3-S3-EVOaffected
Juniper NetworksJunos OS Evolved22.4 < 22.4*affected
Juniper NetworksJunos OS Evolved23.2 < 23.2R2-EVOaffected
Juniper NetworksJunos OS Evolved23.4 < 23.4R2-EVOaffected

Weaknesses

  • CWE-787: CWE-787 Out-of-bounds Write

Workarounds

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.

References