CVE-2026-33803 Junos OS Evolved: A port which has been inadvertently exposed can be reached by an attacker
An attacker can access an internal process via an exposed port, causing information disclosure and increased CPU usage on Juniper network devices.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-33803?
CVE-2026-33803 is a medium-severity vulnerability in Juniper Junos Os Evolved, published on 9 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-923
Which versions are affected by CVE-2026-33803?
It affects 1 product.
Products include Juniper Junos Os Evolved.
How do I fix CVE-2026-33803?
No fix has been published for CVE-2026-33803 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-33803 being exploited?
There is no known exploitation of CVE-2026-33803 in the wild and no public exploit code.
Other vulnerabilities in Juniper Junos Os Evolved
- CVE-2026-21902 Junos OS Evolved: PTX Series: A vulnerability allows a unauthenticated, network-based attacker to execute code as root
- CVE-2023-28983 Junos OS Evolved: Shell Injection vulnerability in the gNOI server
- CVE-2025-21599 Denial of service in Junos OS Evolved
- CVE-2024-47502 Junos OS Evolved: TCP session state is not always cleared on the Routing Engine leading to DoS
- CVE-2024-39531 Junos OS Evolved: ACX 7000 Series: Protocol specific DDoS configuration affects other protocols
Sources
Also known as GHSA-xc4g-8c26-vcmf.