CVE-2025-52951 Junos OS: IPv6 firewall filter fails to match payload-protocol
Attackers can bypass IPv6 firewall filters on Junos OS control plane by exploiting a kernel filter processing flaw that ignores payload-protocol matches.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-52951?
CVE-2025-52951 is a medium-severity vulnerability in Juniper Junos, published on 11 Jul 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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).
Weakness: CWE-693
Which versions are affected by CVE-2025-52951?
It affects 1 product.
Products include Juniper Junos.
How do I fix CVE-2025-52951?
No fix has been published for CVE-2025-52951 yet. Limit exposure of the affected software until one is available.
Is CVE-2025-52951 being exploited?
There is no known exploitation of CVE-2025-52951 in the wild and no public exploit code.
Other vulnerabilities in Juniper Junos
- CVE-2023-36845 Juniper Junos OS EX Series and SRX Series PHP External Variable Modification
- CVE-2020-1631 Juniper Junos OS Path Traversal
- CVE-2025-21590 Juniper Junos OS Improper Isolation or Compartmentalization
- CVE-2023-36851 Juniper Junos OS SRX Series Missing Authentication for Critical Function
- CVE-2023-36844 Juniper Junos OS EX Series PHP External Variable Modification
Sources
Also known as GHSA-wgx4-f5ch-j468.