Out-of-Bounds Write in Juniper Networks Junos OS (CVE-2026-33799)
Summary
Out-of-bounds write in Juniper Networks Junos OS (CVE-2026-33799). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-33799 has been found in Juniper Networks Junos OS.
Risk of unauthorized operations or information disclosure. CVSS score: 4.3/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Juniper Networks Junos OS CVE-2026-33799" on the vendor's site.
CVE-2026-33799 (Juniper Networks Junos OS) — CWE-787 / CVSS v3 4.3
Attack vector: remote (network-reachable) / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Out-of-bounds write (CWE-787) exists in Juniper Networks Junos OS.
Check the vendor advisory for the affected versions of Juniper Networks Junos OS.
Severity: Medium (CVSS 4.3/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Juniper Networks Junos OS を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- patch sirt@juniper.net
- web nvd.nist.gov
- web github.com