CVE-2025-20142
highpriority · track · 0EPSS 0.005 · 45 %ileDEEURUUSEPSS · scored 2026-10-22
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.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- FixedCisco IOS XR Softwarecisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (79)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2025-0546Cisco IOS: Mehrere Schwachstellen ermöglichen Denial of ServiceDeutsch2025-03-12csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Cisco IOS ausnutzen, um einen Denial of Service Angriff durchzuführen.
- cisco-sa-ipv4uni-LfM3cfBuCisco IOS XR Software for ASR 9000 Series Routers IPv4 Unicast Packets Denial of Service Vulnerability2025-03-12csaf · cisco_csafUS
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. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. There are mitigations that address this vulnerability. This advisory is part of the March 2025 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2025 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75548"].
also known as (4)
Other names and identifiers for this entity.
sources
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references (6)
External citations — patches, advisories, analysis.
- https://blog.apnic.net/2024/09/02/crafting-endless-as-paths-in-bgp/cnnvd
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ipv4uni-LfM3cfBucnnvd
- https://blog.apnic.net/2024/09/02/crafting-endless-as-paths-in-bgp/enisa_euvd
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ipv4uni-LfM3cfBuenisa_euvd
- https://blog.apnic.net/2024/09/02/crafting-endless-as-paths-in-bgp/Technical Descriptionnvd
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ipv4uni-LfM3cfBuVendor Advisorynvd
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