CVE-2026-33801: Junos OS and Junos OS Evolved: When a specifically malformed BGP route update is received RPD crashes
An Improper Check for Unusual or Exceptional Conditions vulnerability in the routing protocol daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker sending a specific BGP update over an established BGP session to cause a Denial-of-Service (DoS).
Upon receipt of a specifically malformed non-inet/inet6 unicast BGP update, an RPD crash and restart is triggered, which will cause a complete service outage until routing has reconverged. The rpd crash occurs before the update can be readvertised, so there is no downstream propagation.
This issue affects:
Junos OS versions 25.2 before 25.2R2;
Junos OS Evolved versions 25.2 before 25.2R2-EVO.
This issue doesn't affect Junos OS versions before 25.2R1 nor Junos OS Evolved versions before 25.2R1-EVO.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Juniper Junos OS Evolvedto a version that resolves this vulnerability.Fixed in 25.2R2-EVO - Upgrade
Upgrade
Juniper Junos OS Evolvedto a version that resolves this vulnerability.Fixed in 25.4R1-EVO - Upgrade
Upgrade
Juniper Junos OSto a version that resolves this vulnerability.Fixed in 25.2R2 - Upgrade
Upgrade
Juniper Junos OSto a version that resolves this vulnerability.Fixed in 25.4R1 - Compensating control
Because the RPD crash is triggered by receipt of a specifically malformed non-inet/inet6 unicast BGP update over an established BGP session, ensure only authenticated/authorized BGP peers can send updates to the router (adjacent attacker sending a BGP update over an established BGP session).
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33801?
CVE-2026-33801 has a medium severity level with a score of 6.5.
How can I fix CVE-2026-33801?
To fix CVE-2026-33801, ensure that you update your Junos OS or Junos OS Evolved to the latest patched version provided by Juniper Networks.
What impact does CVE-2026-33801 have on my system?
CVE-2026-33801 can lead to a Denial-of-Service (DoS) condition when a malformed BGP route update is received.
Who is affected by CVE-2026-33801?
CVE-2026-33801 affects all users of Junos OS and Junos OS Evolved operating systems from Juniper Networks.
What components of Juniper’s systems are impacted by CVE-2026-33801?
CVE-2026-33801 impacts the routing protocol daemon (RPD) within Junos OS and Junos OS Evolved.