CVE-2025-52951

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

MEDIUM

5.8

CVSS Score

Published: July 11, 2025 at 02:41 PM UTC

Updated: June 17, 2026 at 09:37 AM UTC

1 product affected across 1 vendorJunos

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Severity

MEDIUM5.8

Exploit prediction

EPSS 0.4%

SSVC

No known exploit

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).

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Junos · Juniper Networks

95%

v < 21.2v < 21.2R3-S921.4 ≤ v < 21.4R3-S1122.2 ≤ v < 22.2R3-S722.4 ≤ v < 22.4R3-S723.2 ≤ v < 23.2R2-S423.4 ≤ v < 23.4R2-S524.2 ≤ v < 24.2R2-S124.4 ≤ v < 24.4R1-S2, 24.4R221.2 21.2 r1 21.2 r1-s1 21.2 r1-s2 21.2 r2 21.2 r2-s1 21.2 r2-s2 21.2 r3 21.2 r3-s1 21.2 r3-s2 21.2 r3-s3 21.2 r3-s4 21.2 r3-s5 21.2 r3-s6 21.2 r3-s7 21.2 r3-s8 21.4 21.4 r1 21.4 r1-s1 21.4 r1-s2 21.4 r2 21.4 r2-s1 21.4 r2-s2 21.4 r3 21.4 r3-s1 21.4 r3-s10 21.4 r3-s2 21.4 r3-s3 21.4 r3-s4 21.4 r3-s5 21.4 r3-s6 21.4 r3-s7 21.4 r3-s8 21.4 r3-s9 22.2 22.2 r1 22.2 r1-s1 22.2 r1-s2 22.2 r2 22.2 r2-s1 22.2 r2-s2 22.2 r3 22.2 r3-s1 22.2 r3-s2 22.2 r3-s3 22.2 r3-s4 22.2 r3-s5 22.2 r3-s6 22.4 22.4 r1 22.4 r1-s1 22.4 r1-s2 22.4 r2 22.4 r2-s1 22.4 r2-s2 22.4 r3 22.4 r3-s1 22.4 r3-s2 22.4 r3-s3 22.4 r3-s4 22.4 r3-s5 22.4 r3-s6 23.2 23.2 r1 23.2 r1-s1 23.2 r1-s2 23.2 r2 23.2 r2-s1 23.2 r2-s2 23.2 r2-s3 23.4 23.4 r1 23.4 r1-s1 23.4 r1-s2 23.4 r2 23.4 r2-s1 23.4 r2-s2 23.4 r2-s3 23.4 r2-s4 24.2 24.2 r1 24.2 r1-s1 24.2 r1-s2 24.2 r2 24.4 24.4 r1 24.4 r2

Affected range stops below 21.2R3-S9, so it looks safe — our inference, not a vendor statement

Affected range stops below 21.4R3-S11, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.2R3-S7, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.4R3-S7, so it looks safe — our inference, not a vendor statement

Affected range stops below 23.2R2-S4, so it looks safe — our inference, not a vendor statement

Affected range stops below 23.4R2-S5, so it looks safe — our inference, not a vendor statement

Affected range stops below 24.2R2-S1, so it looks safe — our inference, not a vendor statement

Affected range stops below 24.4R1-S2, 24.4R2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://supportportal.juniper.net/JSA100055

References (1)

Vendor Advisory

Source: [email protected]

https://supportportal.juniper.net/JSA100055

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.8MEDIUMjuniper

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: CHANGED
Confidentiality: NONE
Integrity: LOW
Availability: NONE

Vector?

Quick Info

StatusANALYZED

CWE

CWE-693

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