Vulnerability in Juniper Junos
CVE-2026-33801
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.
EPSS: 0.002 (6.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Juniper Junos — versions 25.2
- Juniper Junos_os_evolved — versions 25.2
- Juniper Networks Junos Os — versions 25.2
- Juniper Networks Junos Os Evolved — versions 25.2
Weakness classification (CWE)
References
- sirt@juniper.net (vendor-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-33801?
- CVE-2026-33801 is a medium-severity vulnerability in Juniper Junos, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 6.5/10. Published 2026-07-09.
- How severe is CVE-2026-33801?
- Medium severity. CVSS v3 base score is 6.5 out of 10.