Router DoS via Bad IPv4 Packet Handling in Cisco IOS XR ACL/QoS
CVE-2025-20142 Published on March 12, 2025
Cisco IOS XR Software for ASR 9000 Series Routers L2VPN Denial of Service Vulnerability
A vulnerability in the IPv4 access control list (ACL) feature and quality of service (QoS) policy feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition.
This vulnerability is due to the incorrect handling of malformed IPv4 packets that are received on line cards where the interface has either an IPv4 ACL or QoS policy applied. An attacker could exploit this vulnerability by sending crafted IPv4 packets through an affected device. A successful exploit could allow the attacker to cause network processor errors, resulting in a reset or shutdown of the network process. Traffic over that line card would be lost while the line card reloads.
Note: This vulnerability has predominantly been observed in Layer 2 VPN (L2VPN) environments where an IPv4 ACL or QoS policy has been applied to the bridge virtual interface. Layer 3 configurations where the interface has either an IPv4 ACL or QoS policy applied are also affected, though the vulnerability has not been observed.
Vulnerability Analysis
CVE-2025-20142 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
Products Associated with CVE-2025-20142
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Affected Versions
Cisco IOS XR Software:- Version 7.1.15 is affected.
- Version 7.1.2 is affected.
- Version 6.7.2 is affected.
- Version 7.1.25 is affected.
- Version 7.1.3 is affected.
- Version 6.7.3 is affected.
- Version 7.3.1 is affected.
- Version 7.4.1 is affected.
- Version 6.8.1 is affected.
- Version 7.3.2 is affected.
- Version 7.5.1 is affected.
- Version 7.6.1 is affected.
- Version 7.5.2 is affected.
- Version 7.3.3 is affected.
- Version 6.8.2 is affected.
- Version 7.7.1 is affected.
- Version 7.4.2 is affected.
- Version 7.3.4 is affected.
- Version 6.7.35 is affected.
- Version 6.9.1 is affected.
- Version 7.6.2 is affected.
- Version 7.8.1 is affected.
- Version 7.5.3 is affected.
- Version 7.7.2 is affected.
- Version 6.9.2 is affected.
- Version 7.9.1 is affected.
- Version 7.8.2 is affected.
- Version 7.5.4 is affected.
- Version 7.8.22 is affected.
- Version 7.10.1 is affected.
- Version 7.9.2 is affected.
- Version 7.3.5 is affected.
- Version 7.5.5 is affected.
- Version 7.8.23 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.