CVE-2026-33803: Junos OS Evolved: A port which has been inadvertently exposed can be reached by an attacker
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Juniper Networks Junos OS Evolvedto a version that resolves this vulnerability.Fixed in 23.2R2-S7-EVO - Upgrade
Upgrade
Juniper Networks Junos OS Evolvedto a version that resolves this vulnerability.Fixed in 23.4R2-S8-EVO - Upgrade
Upgrade
Juniper Networks Junos OS Evolvedto a version that resolves this vulnerability.Fixed in 24.2R2-S5-EVO - Upgrade
Upgrade
Juniper Networks Junos OS Evolvedto a version that resolves this vulnerability.Fixed in 24.4R2-S4-EVO - Upgrade
Upgrade
Juniper Networks Junos OS Evolvedto a version that resolves this vulnerability.Fixed in 25.2R2-S1-EVO - Upgrade
Upgrade
Juniper Networks Junos OS Evolvedto a version that resolves this vulnerability.Fixed in 25.4R1-S2-EVO - Upgrade
Upgrade
Juniper Networks Junos OS Evolvedto a version that resolves this vulnerability.Fixed in 25.4R2-EVO - Upgrade
Upgrade
Juniper Networks Junos OS Evolvedto a version that resolves this vulnerability.Fixed in 26.2R1-EVO
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33803?
CVE-2026-33803 has a medium severity score of 6.9.
What impact can an attacker have exploiting CVE-2026-33803?
Exploitation of CVE-2026-33803 can lead to limited information disclosure and availability issues.
How do I fix CVE-2026-33803?
To fix CVE-2026-33803, ensure that proper communication channel restrictions are enforced in your Junos OS Evolved configuration.
Who is affected by CVE-2026-33803?
Devices running Juniper Networks Junos OS Evolved are affected by CVE-2026-33803.
What kind of vulnerability is CVE-2026-33803?
CVE-2026-33803 is an Improper Restriction of Communication Channel to Intended Endpoints vulnerability.