CVE-2024-47490 in Junos OS Evolved
Summary
by MITRE • 10/11/2024
An Improper Restriction of Communication Channel to Intended Endpoints vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS Evolved on ACX 7000 Series allows an unauthenticated, network based attacker to cause increased consumption of resources, ultimately resulting in a Denial of Service (DoS).
When specific transit MPLS packets are received by the PFE, these packets are internally forwarded to the Routing Engine (RE), rather than being handled appropriately. Continuous receipt of these MPLS packets causes resources to be exhausted. MPLS config is not required to be affected by this issue.
This issue affects Junos OS Evolved ACX 7000 Series:
* All versions before 21.4R3-S9-EVO, * 22.2-EVO before 22.2R3-S4-EVO, * 22.3-EVO before 22.3R3-S3-EVO, * 22.4-EVO before 22.4R3-S2-EVO, * 23.2-EVO before 23.2R2-EVO, * 23.4-EVO before 23.4R1-S1-EVO, 23.4R2-EVO.
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Analysis
by VulDB Data Team • 01/26/2026
The vulnerability described in CVE-2024-47490 represents a critical flaw in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS Evolved running on ACX 7000 Series devices. This issue falls under the category of improper restriction of communication channels, specifically manifesting as a failure to properly validate and control packet forwarding behavior within the network infrastructure. The vulnerability stems from the PFE's incorrect handling of specific transit MPLS packets that should be processed appropriately but instead get internally forwarded to the Routing Engine, creating an abnormal resource consumption pattern that can lead to system instability and denial of service conditions.
The technical implementation of this vulnerability involves the PFE's packet processing logic where transit MPLS packets are not being correctly filtered or handled according to established network protocols. When these specific MPLS packets are received, the system's internal forwarding mechanism redirects them to the Routing Engine instead of processing them through the appropriate channel handling procedures. This misconfiguration creates a resource exhaustion scenario where the Routing Engine becomes overwhelmed with packets that should have been managed by the PFE's dedicated forwarding mechanisms. The vulnerability is particularly concerning because it does not require any specific MPLS configuration to be present on the device, making it exploitable across a wide range of network environments.
The operational impact of CVE-2024-47490 extends beyond simple service disruption to potentially compromise network availability and reliability across critical infrastructure. Network administrators may observe gradual performance degradation followed by complete service outages as system resources become exhausted. The vulnerability affects multiple software versions across different release branches, indicating a persistent flaw in the codebase that has not been adequately addressed through previous patches. This widespread impact affects devices running various versions of Junos OS Evolved including those in the 21.4R3-S9-EVO, 22.2-EVO, 22.3-EVO, 22.4-EVO, 23.2-EVO, and 23.4-EVO release lines, creating a significant attack surface for malicious actors who can exploit this weakness without requiring authentication or specific network privileges.
The vulnerability aligns with CWE-284, which addresses improper access control in network communication systems, and represents a clear violation of proper resource management principles. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, which covers network denial of service attacks through resource exhaustion, and T1566.001, covering spearphishing via email attacks that could potentially leverage such vulnerabilities. Network defenders should be particularly concerned about the lack of authentication requirements for exploitation, which means that attackers can initiate this attack from external network positions without requiring any prior access credentials. The resource consumption pattern creates a predictable attack vector that can be automated, making it particularly dangerous for enterprise networks that depend on continuous availability.
Mitigation strategies for CVE-2024-47490 should prioritize immediate deployment of official Juniper patches for affected software versions, with particular attention to the specific version ranges mentioned in the vulnerability description. Network administrators should implement traffic filtering mechanisms to prevent transit MPLS packets from reaching vulnerable PFE components, though this requires careful network design to avoid disrupting legitimate traffic flows. The recommended approach involves upgrading to patched versions of Junos OS Evolved, with the specific patch releases noted in Juniper's security advisories for each affected version line. Additionally, implementing network monitoring solutions that can detect unusual resource consumption patterns and packet forwarding behaviors will help in early detection of exploitation attempts. Organizations should also consider implementing network segmentation strategies to limit the potential impact of such attacks and establish incident response procedures that can quickly address resource exhaustion conditions before they escalate to complete service outages.