CVE-2026-33803 in Junos OS Evolved
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...
Quick answer
Juniper Networks Junos OS Evolved should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- Junos OS Evolved 0 to before 23.2R2-S7-EVO
- Junos OS Evolved 23.4 to before 23.4R2-S8-EVO
- Junos OS Evolved 24.2 to before 24.2R2-S5-EVO
- Junos OS Evolved 24.4 to before 24.4R2-S4-EVO
- Junos OS Evolved 25.2 to before 25.2R2-S1-EVO
- Junos OS Evolved 25.4 to before 25.4R1-S2-EVO
Fixed versions
- Junos OS Evolved 23.2R2-S7-EVO or later
- Junos OS Evolved 23.4R2-S8-EVO or later
- Junos OS Evolved 24.2R2-S5-EVO or later
- Junos OS Evolved 24.4R2-S4-EVO or later
- Junos OS Evolved 25.2R2-S1-EVO or later
- Junos OS Evolved 25.4R1-S2-EVO or later
How to fix it
Update Junos OS Evolved. The old network OS can allow denial of service, data exposure, or bypass, depending on the CVE.
- Check the exact Juniper platform and release train.
- Upgrade to a fixed release: Junos OS Evolved 23.2R2-S7-EVO or later, Junos OS Evolved 23.4R2-S8-EVO or later, Junos OS Evolved 24.2R2-S5-EVO or later, Junos OS Evolved 24.4R2-S4-EVO or later, Junos OS Evolved 25.2R2-S1-EVO or later, Junos OS Evolved 25.4R1-S2-EVO or later.
- Follow Juniper maintenance and rollback guidance.
- Watch routing, VPN, flow, CPU, and crash logs after the update.
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Verify the fix
- Run show version and confirm the fixed Junos release is installed.
- Scan again and confirm CVE-2026-33803 is gone.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-33803?
Juniper Networks Junos OS Evolved versions listed as affected should be reviewed: Junos OS Evolved 0 to before 23.2R2-S7-EVO, Junos OS Evolved 23.4 to before 23.4R2-S8-EVO, Junos OS Evolved 24.2 to before 24.2R2-S5-EVO, Junos OS Evolved 24.4 to before 24.4R2-S4-EVO, Junos OS Evolved 25.2 to before 25.2R2-S1-EVO, Junos OS Evolved 25.4 to before 25.4R1-S2-EVO.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.