CVE-2025-52951
Junos OS: IPv6 firewall filter fails to match payload-protocol
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).
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Junos OS: IPv6 firewall filter fails to match payload-protocol
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).
- Record
CVE-2025-52951- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/AU:Y/R:U/RE:M - CVSS 3.1
- 5.8 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N - Weakness
- CWE-693
- Updated
- 2026-11-02
EUVDEUVD-2025-21160
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).
- Record
EUVD-2025-21160- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/AU:Y/R:U/RE:M - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-wgx4-f5ch-j468
A Protection Mechanism Failure vulnerability in kernel filter processing of Juniper Networks...
A Protection Mechanism Failure vulnerability in kernel filter processing of Juniper Networks Junos OS allows an attacker sending IPv6 traffic to an interface 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.
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).
- Record
GHSA-wgx4-f5ch-j468- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:X/RE:M/U:X - CVSS 3.1
- 5.8 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N - Weakness
- CWE-693
- Updated
- 2026-11-02
NVD
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).
- Record
CVE-2025-52951- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:X/RE:M/U:X - CVSS 3.1
- 5.8 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N - Weakness
- CWE-693
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-52951 is a medium vulnerability (CVSS 6.9) in Juniper Junos, published July 11, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.38%, the 32nd percentile. No source names a fixed version.