Vulnerability in Juniper Junos OS Evolved (CVE-2026-33803)
Summary
Vulnerability in Juniper Junos OS Evolved (CVE-2026-33803). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
An Improper Restriction of Communication Channel to Intended Endpoints vulnerability in Juniper Networks Junos OS Evolved allows an unauthenticated, network-based attacker to cause a limited information disclosure and availability impact to the device.
Due to a wrong initialization, a process which should only be able to communicate internally within the device can be reached over the network via an open port. This leads to a device being inadvertently exposed and increased CPU cycles spent processing ingress packets.
This issue affects Junos OS Evolved:
- all versions before 23.2R2-S7-EVO,
- 23.4 versions before 23.4R2-S8-EVO,
- 24.2 versions before 24.2R2-S5-EVO,
- 24.4 versions before 24.4R2-S4-EVO,
- 25.2 versions before 25.2R2-S1-EVO,
- 25.4 versions before 25.4R1-S2-EVO.
Source: NIST National Vulnerability Database 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-2026-33803 has been found in Juniper Junos OS Evolved.
Risk of unauthorized operations or information disclosure. CVSS score: 6.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Juniper Junos OS Evolved CVE-2026-33803" on the vendor's site.
CVE-2026-33803 (Juniper Junos OS Evolved) — CWE-923 / CVSS v3 6.5
Attack vector: remote (network-reachable) / unauthenticated / 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.
A vulnerability (CWE-923) exists in Juniper Junos OS Evolved.
Check the vendor advisory for the affected versions of Juniper Junos OS Evolved.
Severity: Medium (CVSS 6.5/10). 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 Junos OS Evolved 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