Juniper Junos OS up to 24.4R1-S2 Kernel Filter protection mechanism

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.4	$0-$5k	0.00

Summaryinfo

A vulnerability described as problematic has been identified in Juniper Junos OS up to 24.4R1-S2. The affected element is an unknown function of the component Kernel Filter. The manipulation results in protection mechanism. This vulnerability is identified as CVE-2025-52951. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Juniper Junos OS up to 24.4R1-S2. Affected is an unknown code block of the component Kernel Filter. The manipulation with an unknown input leads to a protection mechanism vulnerability. CWE is classifying the issue as CWE-693. The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product. This is going to have an impact on integrity. CVE summarizes:

A Protection Mechanism Failure vulnerability in kernel filter processing of Juniper Networks Junos OS allows an attacker sending IPv6 traffic destined to the device to effectively bypass any firewall filtering configured on the interface. Due to an issue with Junos OS kernel filter processing, the 'payload-protocol' match is not being supported, causing any term containing it to accept all packets without taking any other action. In essence, these firewall filter terms were being processed as an 'accept' for all traffic on the interface destined for the control plane, even when used in combination with other match criteria. This issue only affects firewall filters protecting the device's control plane. Transit firewall filtering is unaffected by this vulnerability. This issue affects Junos OS: * all versions before 21.2R3-S9, * from 21.4 before 21.4R3-S11, * from 22.2 before 22.2R3-S7, * from 22.4 before 22.4R3-S7, * from 23.2 before 23.2R2-S4, * from 23.4 before 23.4R2-S5, * from 24.2 before 24.2R2-S1, * from 24.4 before 24.4R1-S2, 24.4R2. This is a more complete fix for previously published CVE-2024-21607 (JSA75748).

The advisory is available at supportportal.juniper.net. This vulnerability is traded as CVE-2025-52951 since 06/23/2025. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 04/07/2026).

The vulnerability scanner Nessus provides a plugin with the ID 305081 (Juniper Junos OS Vulnerability (JSA100055)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 21.2R3-S9, 21.4R3-S11, 22.2R3-S7, 22.4R3-S7, 23.2R2-S4, 23.4R2-S5, 24.2R2-S1, 24.4R1-S2 or 24.4R2 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (305081), EUVD (EUVD-2025-21160) and CERT Bund (WID-SEC-2025-1519). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

Juniper MX Series
Juniper JUNOS
Juniper SRX Series
Juniper Security Director
Juniper Junos Space

Productinfo

Type

Router Operating System

Vendor

Juniper

Name

Junos OS

Version

License

commercial

Website

Vendor: https://www.juniper.net/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔍
CNA CVSS-BT Score: 🔍
CNA Vector: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.4

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

CNA Base Score: 5.8
CNA Vector (juniper): 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Protection mechanism
CWE: CWE-693
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 305081
Nessus Name: Juniper Junos OS Vulnerability (JSA100055)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Junos OS 21.2R3-S9/21.4R3-S11/22.2R3-S7/22.4R3-S7/23.2R2-S4/23.4R2-S5/24.2R2-S1/24.4R1-S2/24.4R2