CVE-2025-52951

Junos OS: IPv6 firewall filter fails to match payload-protocol

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).

Remediation

Solution:

  • The following software releases have been updated to resolve this specific issue: 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, 25.2R1, and all subsequent releases.

Workaround:

  • Utilize 'next-header' match instead of 'payload-protocol' in any firewall filter configurations.

Category

6.9
CVSS
Severity: Medium
CVSS 4.0 •
CVSS 3.1 •
EPSS 0.05%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS
Published at:
Updated at:

References

Link Tags
https://supportportal.juniper.net/JSA100055 vendor advisory

Frequently Asked Questions

What is the severity of CVE-2025-52951?
CVE-2025-52951 has been scored as a medium severity vulnerability.
How to fix CVE-2025-52951?
To fix CVE-2025-52951: The following software releases have been updated to resolve this specific issue: 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, 25.2R1, and all subsequent releases.
Is CVE-2025-52951 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2025-52951 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-52951?
CVE-2025-52951 affects Juniper Networks Junos OS.
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