CVE-2025-30644 in Junos OS
Summary
by MITRE • 04/09/2025
A Heap-based Buffer Overflow vulnerability in the flexible PIC concentrator (FPC) of Juniper Networks Junos OS on EX2300, EX3400, EX4100, EX4300, EX4300MP, EX4400, EX4600, EX4650-48Y, and QFX5k Series allows an attacker to send a specific DHCP packet to the device, leading to an FPC crash and restart, resulting in a Denial of Service (DoS). Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition.
Under a rare timing scenario outside the attacker's control, memory corruption may be observed when DHCP Option 82 is enabled, leading to an FPC crash and affecting packet forwarding. Due to the nature of the heap-based overflow, exploitation of this vulnerability could also lead to remote code execution within the FPC, resulting in complete control of the vulnerable component. This issue affects Junos OS on EX2300, EX3400, EX4100, EX4300, EX4300MP, EX4400, EX4600, EX4650-48Y, and QFX5k Series:
* All versions before 21.4R3-S9, * from 22.2 before 22.2R3-S5, * from 22.4 before 22.4R3-S5, * from 23.2 before 23.2R2-S3, * from 23.4 before 23.4R2-S3, * from 24.2 before 24.2R2.
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Analysis
by VulDB Data Team • 04/29/2026
The vulnerability identified as CVE-2025-30644 represents a heap-based buffer overflow within the flexible PIC concentrator component of Juniper Networks Junos OS operating on several EX and QFX series switches. This flaw manifests when the device receives a specifically crafted DHCP packet, triggering an FPC crash and subsequent restart that results in denial of service. The vulnerability is particularly concerning due to its potential for sustained denial of service conditions when the malicious packet is repeatedly received and processed, effectively rendering the affected network infrastructure unavailable to legitimate users. The technical nature of this flaw places it squarely within the purview of CWE-122, which describes heap-based buffer overflows that occur when insufficient bounds checking is performed on heap-allocated memory regions.
The operational impact of this vulnerability extends beyond simple service disruption to potentially encompass remote code execution within the FPC context, as indicated by the exploitation potential described in the advisory. This remote code execution capability, while dependent on specific timing conditions outside an attacker's direct control, introduces a significant security risk that could allow an adversary to gain complete control over the vulnerable component. The memory corruption observed under rare timing scenarios when DHCP Option 82 is enabled further compounds the risk, as it could lead to unpredictable behavior and packet forwarding disruptions that compromise network stability and reliability. This behavior aligns with ATT&CK technique T1203, which involves exploitation of software vulnerabilities for remote code execution, and T1499, which covers network denial of service attacks.
Mitigation strategies for CVE-2025-30644 should prioritize immediate deployment of patched firmware versions across all affected hardware platforms, including EX2300, EX3400, EX4100, EX4300, EX4300MP, EX4400, EX4600, EX4650-48Y, and QFX5k Series devices. Network administrators should also implement DHCP filtering mechanisms to prevent the reception of malformed DHCP packets, particularly those containing suspicious DHCP Option 82 configurations. Additionally, monitoring systems should be configured to detect unusual FPC restart patterns or service disruptions that could indicate exploitation attempts. The vulnerability's classification as a heap-based buffer overflow (CWE-122) indicates that defensive measures should include heap memory sanitization techniques and bounds checking enforcement, while the potential for remote code execution necessitates network segmentation and access control measures to limit the impact scope. Organizations should also consider implementing intrusion detection systems capable of identifying and blocking the specific DHCP packet patterns associated with this vulnerability, as outlined in ATT&CK tactic TA0043, which encompasses detection of malicious network traffic patterns.