CVE-2025-21600 Denial of service in Junos OS
An unauthenticated BGP peer can cause a denial of service by sending malformed packets to Junos OS systems with specific BGP options enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-21600?
CVE-2025-21600 is a high-severity denial of service vulnerability in Juniper Junos, published on 9 Jan 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
An Out-of-Bounds Read vulnerability in
the routing protocol daemon (rpd) of
Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, logically adjacent BGP peer sending a specifically malformed BGP packet to cause rpd to crash and restart, resulting in a Denial of Service (DoS). Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition.
This issue only affects systems configured in either of two ways:
* systems with BGP traceoptions enabled
* systems with BGP family traffic-engineering (BGP-LS) configured
and can be exploited from a directly connected and configured BGP peer.
This issue affects iBGP and eBGP
with
any address family
configured, and both IPv4 and IPv6 are affected by this vulnerability.
This issue affects:
Junos OS:
*
from 21.4 before 21.4R3-S9, * from 22.2 before 22.2R3-S5, * from 22.3 before 22.3R3-S4, * from 22.4 before 22.4R3-S5, * from 23.2 before 23.2R2-S3, * from 23.4 before 23.4R2-S3, * from 24.2 before 24.2R1-S2, 24.2R2;
Junos OS Evolved:
* from 21.4-EVO before 21.4R3-S9-EVO, * from 22.2-EVO before 22.2R3-S5-EVO, * from 22.3-EVO before 22.3R3-S4-EVO, * from 22.4-EVO before 22.4R3-S5-EVO, * from 23.2-EVO before 23.2R2-S3-EVO, * from 23.4-EVO before 23.4R2-S2-EVO, * from 24.2-EVO before 24.2R1-S2-EVO, 24.2R2-EVO.
This issue does not affect versions of Junos OS prior to 21.3R1.
This issue does not affect versions of Junos OS Evolved prior to 21.3R1-EVO.
This is a similar, but different vulnerability than the issue reported as CVE-2024-39516.
Weakness: CWE-125
Which versions are affected by CVE-2025-21600?
It affects 2 products.
Products include Juniper Junos, Juniper Junos Os Evolved.
How do I fix CVE-2025-21600?
No fix has been published for CVE-2025-21600 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-21600 being exploited?
There is no known exploitation of CVE-2025-21600 in the wild and no public exploit code.
Other vulnerabilities in Juniper Junos
- CVE-2023-36845 Juniper Junos OS EX Series and SRX Series PHP External Variable Modification
- CVE-2020-1631 Juniper Junos OS Path Traversal
- CVE-2025-21590 Juniper Junos OS Improper Isolation or Compartmentalization
- CVE-2023-36851 Juniper Junos OS SRX Series Missing Authentication for Critical Function
- CVE-2023-36844 Juniper Junos OS EX Series PHP External Variable Modification
Sources
Also known as GHSA-p52f-fg64-jqxw.