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CVE-2025-20189

HIGHCVSS 7.4/10EPSS 0.20%

Last modified

CVE-2025-20189 is a high-severity vulnerability rated 7.4/10 on the CVSS scale. A vulnerability in the Cisco Express Forwarding functionality of Cisco IOS XE Software for Cisco ASR 903 Aggregation Services Routers with Route Switch Processor 3 (RSP3C) could allow an unauthenticated, adjacent attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper memory management when Cisco IOS XE Software is processing Address Resolution Protocol (ARP) messages. An attacker could exploit this vulnerability by sending crafted ARP messages at a high rate over a period of time to an affected device. EPSS estimates a 0.20% chance of exploitation in the next 30 days.

Description

A vulnerability in the Cisco Express Forwarding functionality of Cisco IOS XE Software for Cisco ASR 903 Aggregation Services Routers with Route Switch Processor 3 (RSP3C) could allow an unauthenticated, adjacent attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper memory management when Cisco IOS XE Software is processing Address Resolution Protocol (ARP) messages. An attacker could exploit this vulnerability by sending crafted ARP messages at a high rate over a period of time to an affected device. A successful exploit could allow the attacker to exhaust system resources, which eventually triggers a reload of the active route switch processor (RSP). If a redundant RSP is not present, the router reloads.

Metrics

CVSS 3.1
7.4/10

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

EPSS Probability
0.20%

10.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
CiscoIos Xe3.16.0cs
CiscoIos Xe3.16.0s
CiscoIos Xe3.16.1as
CiscoIos Xe3.16.1s
CiscoIos Xe3.16.2as
CiscoIos Xe3.16.2bs
CiscoIos Xe3.16.2s
CiscoIos Xe3.16.3as
CiscoIos Xe3.16.3s
CiscoIos Xe3.16.4as
CiscoIos Xe3.16.4bs
CiscoIos Xe3.16.4ds
CiscoIos Xe3.16.4s
CiscoIos Xe3.16.5s
CiscoIos Xe3.16.6bs
CiscoIos Xe3.16.6s
CiscoIos Xe3.16.7as
CiscoIos Xe3.16.7bs
CiscoIos Xe3.16.7s
CiscoIos Xe3.16.8s
CiscoIos Xe3.16.9s
CiscoIos Xe3.16.10s
CiscoIos Xe3.17.0s
CiscoIos Xe3.17.1as
CiscoIos Xe3.17.1s
CiscoIos Xe3.17.2s
CiscoIos Xe3.17.3s
CiscoIos Xe3.17.4s
CiscoIos Xe3.18.0as
CiscoIos Xe3.18.0s
CiscoIos Xe3.18.0sp
CiscoIos Xe3.18.1asp
CiscoIos Xe3.18.1bsp
CiscoIos Xe3.18.1csp
CiscoIos Xe3.18.1s
CiscoIos Xe3.18.1sp
CiscoIos Xe3.18.2asp
CiscoIos Xe3.18.2s
CiscoIos Xe3.18.2sp
CiscoIos Xe3.18.3asp
CiscoIos Xe3.18.3bsp
CiscoIos Xe3.18.3s
CiscoIos Xe3.18.3sp
CiscoIos Xe3.18.4s
CiscoIos Xe3.18.4sp
CiscoIos Xe3.18.5sp
CiscoIos Xe3.18.6sp
CiscoIos Xe3.18.7sp
CiscoIos Xe3.18.8asp
CiscoIos Xe3.18.9sp

Showing 50 of 266 affected configurations. See NVD for the full list.

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2025-20189?
A vulnerability in the Cisco Express Forwarding functionality of Cisco IOS XE Software for Cisco ASR 903 Aggregation Services Routers with Route Switch Processor 3 (RSP3C) could allow an unauthenticated, adjacent attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper memory management when Cisco IOS XE Software is processing Address Resolution Protocol (ARP) messages. An attacker could exploit this vulnerability by sending crafted ARP messages at a high rate over a period of time to an affected device. A successful exploit could allow the attacker to exhaust system resources, which eventually triggers a reload of the active route switch processor (RSP). If a redundant RSP is not present, the router reloads.
How severe is CVE-2025-20189?
CVE-2025-20189 has a CVSS score of 7.4/10 (HIGH severity). The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.
How do I fix CVE-2025-20189?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-20189?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST