CVE-2025-52947: Junos OS: ACX Series: When 'hot-standby' mode is configured for an L2 circuit, interface flap causes the FEB to crash
An Improper Handling of Exceptional Conditions vulnerability in route processing of Juniper Networks Junos OS on specific end-of-life (EOL) ACX Series platforms allows an attacker to crash the Forwarding Engine Board (FEB) by flapping an interface, leading to a Denial of Service (DoS).
On ACX1000, ACX1100, ACX2000, ACX2100, ACX2200, ACX4000, ACX5048, and ACX5096 devices, FEB0 will crash when the primary path port of the L2 circuit IGP (Interior Gateway Protocol) on the local device goes down. This issue is seen only when 'hot-standby' mode is configured for the L2 circuit.
This issue affects Junos OS on ACX1000, ACX1100, ACX2000, ACX2100, ACX2200, ACX4000, ACX5048, and ACX5096:
all versions before 21.2R3-S9.
Affected Software
Remediation
Information
Event History
Frequently Asked Questions
What is the severity of CVE-2025-52947?
CVE-2025-52947 is classified as a high severity vulnerability due to its potential to cause a Denial of Service.
How do I fix CVE-2025-52947?
To mitigate CVE-2025-52947, it is recommended to upgrade Junos OS to a version beyond 21.2R3-S9 where the vulnerability is addressed.
What systems are affected by CVE-2025-52947?
CVE-2025-52947 affects specific end-of-life ACX Series platforms running vulnerable versions of Juniper Networks Junos OS.
What kind of attack does CVE-2025-52947 facilitate?
CVE-2025-52947 allows attackers to initiate a Denial of Service by flapping interfaces, causing the Forwarding Engine Board to crash.
Is there a workaround for CVE-2025-52947?
Currently, no specific workarounds are provided for CVE-2025-52947, and upgrading the software is the recommended action.