CVE-2025-21593 Denial of service in Junos OS
An unauthenticated attacker can crash the routing daemon on Juniper devices with SRv6 enabled by sending malformed BGP updates, causing a denial of service.
- 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-2025-21593?
CVE-2025-21593 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 Improper Control of a Resource Through its Lifetime vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated network-based attacker to cause a Denial-of-Service (DoS).
On devices with SRv6 (Segment Routing over IPv6) enabled, an attacker can send a malformed BGP UPDATE packet which will cause the rpd to crash and restart. Continued receipt of these UPDATE packets will cause a sustained DoS condition.
This issue affects iBGP and eBGP, and both IPv4 and IPv6 are affected by this vulnerability.This issue affects Junos OS:
* All versions before 21.2R3-S9, * from 21.4 before 21.4R3-S10, * from 22.2 before 22.2R3-S5, * from 22.3 before 22.3R3-S4, * from 22.4 before 22.4R3-S3, * from 23.2 before 23.2R2-S2, * from 23.4 before 23.4R2;
and Junos OS Evolved:
* All versions before 21.2R3-S9-EVO, * from 21.4-EVO before 21.4R3-S10-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-S3-EVO, * from 23.2-EVO before 23.2R2-S2-EVO, * from 23.4-EVO before 23.4R2-EVO.
Weakness: CWE-664
Which versions are affected by CVE-2025-21593?
It affects 2 products.
Products include Juniper Junos, Juniper Junos Os Evolved.
How do I fix CVE-2025-21593?
No fix has been published for CVE-2025-21593 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-2025-21593 being exploited?
There is no known exploitation of CVE-2025-21593 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-3wvw-m4vx-cj7h.