#VU107434 Improper handling of additional special element in Juniper Junos OS - CVE-2025-30656

Vulnerability identifier: #VU107434

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/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-2025-30656

CWE-ID: N/A

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Juniper Junos OS
Operating systems & Components / Operating system

Vendor: Juniper Networks, Inc.

Description

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

The vulnerability exists due to improper handling of additional special element error in the Packet Forwarding Engine (PFE). A remote non-authenticated attacker can cause a Denial-of-Service (DoS).

If the SIP ALG processes specifically formatted SIP invites, a memory corruption will occur which will lead to a crash of the FPC processing these packets.

Although the system will automatically recover with the restart of the FPC, subsequent SIP invites will cause the crash again and lead to a sustained DoS.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Juniper Junos OS: before 21.2R3-S9, 21.2R3-S9

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External links
https://supportportal.juniper.net/s/article/2025-04-Security-Bulletin-Junos-OS-MX-Series-SRX-Series-Processing-of-specific-SIP-INVITE-messages-by-the-SIP-ALG-will-lead-to-an-FPC-crash-CVE-2025-30656

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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