Juniper Junos OS SNMPv3 Out-of-bounds Write Memory Leak DoS (CVE-2026-33799)

Vulnerability Overview Vulnerability Name: SNMPv3 requests in Junos OS and Junos OS Evolved cause memory leak and snmpd crash CVE ID: CVE-2026-33799 Severity: High CVSS Score: - CVSS v3.1: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) - CVSS v4.0: 8.7 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:AI/AI:R/A/VC:RE/M:U/Green) Impact Scope Affected Products: All versions of Junos OS and Junos OS Evolved Specific Versions: - Junos OS: - All versions prior to 21.2R3-S8 - 21.4 to 21.4R3-S7 - 22.1 to 22.1R3-S6 - 22.2 to 22.2R3-S4 - 22.3 to 22.3R3-S3 - 22.4 to 22.4R3-S2 - 23.2 to 23.2R2 - 23.4 to 23.4R2 - Junos OS Evolved: - All versions prior to 21.2R3-S8-EVO - 21.4 to 21.4R3-S7-EVO - All 22.1-EVO versions - 22.2 to 22.2R3-S4-EVO - 22.3 to 22.3R3-S3-EVO - All 22.4-EVO versions - 23.2 to 23.2R2-EVO - 23.4 to 23.4R2-EVO Remediation Fixed Versions: - Junos OS: 21.2R3-S6, 21.4R3-S7, 22.1R3-S6, 22.2R3-S4, 22.3R3-S3, 22.3R2, 22.4R2, 24.2R1, and subsequent versions - 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 subsequent versions Additional Information Description: An out-of-bounds write vulnerability in the SNMP daemon (snmpd) allows an authenticated network attacker to trigger a memory leak by sending specific valid SNMPv3 queries. As these queries are continuously received, the snmpd process exhausts its memory, leading to process crashes and restarts, which impacts the ability to monitor systems via SNMP. Monitoring Method: Memory usage can be monitored using the following command: Configuration Requirements: SNMPv3 must be configured. For example: Known Exploits: Juniper SIRT is currently aware of no malicious exploitation of this vulnerability. Workarounds: There are no known workarounds. To reduce the risk of malicious exploitation, restrict the sources accessing the device via SNMPv3 using access lists or firewall filters. Modification History 2026-07-08: Initial release Related Information KB16413: Juniper Networks SIRT Quarterly Security Advisory Release Process Overview KB16766: Which versions are vulnerable? KB16446: Common Vulnerability Scoring System (CVSS) and Juniper Security Advisories Report a Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team

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Juniper Junos OS SNMPv3 Out-of-bounds Write Memory Leak DoS (CVE-2026-33799)