Improper check for unusual or exceptional conditions in Junos OS Evolved and Juniper Junos OS

1) Improper check for unusual or exceptional conditions

EUVDB-ID: #VU108102

Risk: Medium

CVSSv4.0: 4.9 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-21597

CWE-ID: CWE-754 - Improper Check for Unusual or Exceptional Conditions

Exploit availability: No

Description

The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to improper check for unusual or exceptional conditions error in routing protocol daemon (rpd). A remote non-authenticated attacker can cause Denial of Service (DoS).

 On all Junos OS and Junos OS Evolved platforms, when BGP rib-sharding and update-threading are configured, and a BGP peer flap is done with specific timing, rpd crashes and restarts.

Continuous peer flapping at specific time intervals will result in a sustained Denial of Service (DoS) condition.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Junos OS Evolved: before

Juniper Junos OS: before

CPE2.3

• cpe:2.3:o:juniper_networks:junos_os_evolved:*:*:*:*:*:*:*:*
• cpe:2.3:o:juniper_networks:juniper_junos_os:*:*:*:*:*:*:*:*

External links

https://supportportal.juniper.net/s/article/2025-04-Security-Bulletin-Junos-OS-and-Junos-OS-Evolved-When-BGP-rib-sharding-and-update-threading-are-configured-and-a-peer-flaps-an-rpd-core-is-observed

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.