Juniper Junos OS/Junos OS Evolved Routing Protocol Daemon unusual condition

Summaryinfo

A vulnerability classified as problematic has been found in Juniper Junos OS and Junos OS Evolved. Affected by this issue is some unknown functionality of the component Routing Protocol Daemon. This manipulation causes unusual condition. This vulnerability is handled as CVE-2025-21597. The attack can only be done within the local network. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Juniper Junos OS and Junos OS Evolved (version now known). It has been declared as problematic. Affected by this vulnerability is some unknown processing of the component Routing Protocol Daemon. The manipulation with an unknown input leads to a unusual condition vulnerability. The CWE definition for the vulnerability is CWE-754. The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product. As an impact it is known to affect availability. The summary by CVE is:

An Improper Check for Unusual or Exceptional Conditions vulnerability in routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, logically adjacent BGP peer to 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. This issue affects eBGP and iBGP, in both IPv4 and IPv6 implementations. This issue requires a remote attacker to have at least one established BGP session. The issue can occur with or without logical-systems enabled. This issue affects: Junos OS: * All versions before 20.4R3-S8, * 21.2 versions before 21.2R3-S6, * 21.3 versions before 21.3R3-S5, * 21.4 versions before 21.4R3-S4, * 22.1 versions before 22.1R3-S3, * 22.2 versions before 22.2R3-S1, * 22.3 versions before 22.3R3, * 22.4 versions before 22.4R3. Junos OS Evolved: * All versions before 21.2R3-S6-EVO, * 21.3-EVO versions before 21.3R3-S5-EVO, * 21.4-EVO versions before 21.4R3-S4-EVO, * 22.1-EVO versions before 22.1R3-S3-EVO, * 22.2-EVO versions before :22.2R3-S1-EVO, * 22.3-EVO versions before 22.3R3-EVO, * 22.4-EVO versions before 22.4R3-EVO.

The advisory is shared at kb.juniper.net. This vulnerability is known as CVE-2025-21597 since 12/26/2024. The exploitation appears to be difficult. Access to the local network is required for this attack to succeed. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 01/26/2026).

The vulnerability scanner Nessus provides a plugin with the ID 234109 (Juniper Junos OS Vulnerability (JSA96451)), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (234109). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Router Operating System

Vendor

• Juniper

Name

• Junos OS
• Junos OS Evolved

License

• commercial

Website

• Vendor: https://www.juniper.net/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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