Juniper Junos OS up to 22.2R3-S0/22.4R1 on MX Connectivity Fault Management out-of-bounds write

Summaryinfo

A vulnerability was found in Juniper Junos OS up to 22.2R3-S0/22.4R1 on MX. It has been declared as critical. This vulnerability affects unknown code of the component Connectivity Fault Management. Such manipulation leads to out-of-bounds write. This vulnerability is traded as CVE-2025-52952. Access to the local network is required for this attack to succeed. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Juniper Junos OS up to 22.2R3-S0/22.4R1 on MX. Affected by this issue is some unknown processing of the component Connectivity Fault Management. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is availability. CVE summarizes:

An Out-of-bounds Write vulnerability in the connectivity fault management (CFM) daemon of Juniper Networks Junos OS on MX Series with MPC-BUILTIN, MPC1 through MPC9 line cards allows an unauthenticated adjacent attacker to send a malformed packet to the device, leading to an FPC 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 affects Juniper Networks: Junos OS: * All versions before 22.2R3-S1, * from 22.4 before 22.4R2. This feature is not enabled by default.

The advisory is available at supportportal.juniper.net. This vulnerability is handled as CVE-2025-52952 since 06/23/2025. The exploitation is known to be easy. Access to the local network is required for this attack to succeed. No form of authentication is required for exploitation. 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 04/27/2026).

The vulnerability scanner Nessus provides a plugin with the ID 310426 (Juniper Junos OS Vulnerability (JSA100058)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 22.2R3-S1 or 22.4R2 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (310426) 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

• 22.2R3-S0
• 22.4R1

License

• commercial

Website

• Vendor: https://www.juniper.net/

CPE 2.3info

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CPE 2.2info

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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