CVE-2025-30660: MX Series: Decapsulation of specific GRE packets leads to PFE reset

An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).When processing a high rate of specific GRE traffic destined to the device, the respective PFE will hang causing traffic forwarding to stop.

Published 9 Apr 2025

Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.

Affected and fixed versions

Product / branch	Fixed in
Junos OS (MX Series) 0	21.2R3-S9 or later
Junos OS (MX Series) 21.4	21.4R3-S8 or later
Junos OS (MX Series) 22.2	22.2R3-S4 or later
Junos OS (MX Series) 22.4	22.4R3-S5 or later
Junos OS (MX Series) 23.2	23.2R2-S2 or later
Junos OS (MX Series) 23.4	23.4R2 or later

Always confirm against the vendor advisory, which lists every fixed hotfix.

What it is

When this issue occurs the following logs can be observed:

<fpc #> MQSS(0): LI-3: Received a parcel with more than 512B accompanying data CHASSISD_FPC_ASIC_ERROR: ASIC Error detected <...>

This issue affects Junos OS:

all versions before 21.2R3-S9,
21.4 versions before 21.4R3-S8,
22.2 versions before 22.2R3-S4,
22.4 versions before 22.4R3-S5,
23.2 versions before 23.2R2-S2,
23.4 versions before 23.4R2.

Workarounds

There are no known workarounds for this issue.

Exploitation

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

KEV status, EPSS score and vendor data refreshed automatically, last on 13 Oct 2026.