Adjacent denial of service via ARP flooding
Published Sep 10, 2025 · Updated Sep 10, 2025
Denial of service in Cisco IOS XR Software allows attackers on the adjacent network to make affected devices completely unresponsive. The ARP implementation accepts a high, sustained traffic rate on an addressed, Up management interface without sufficient processing limits, overwhelming ARP handling and triggering a broadcast storm. Exposure requires an IP-addressed management interface in the Up state; exploitation degrades performance, drops management connectivity, and can halt device responsiveness.
Summary
What happened
Denial of service in Cisco IOS XR Software allows attackers on the adjacent network to make affected devices completely unresponsive. The ARP implementation accepts a high, sustained traffic rate on an addressed, Up management interface without sufficient processing limits, overwhelming ARP handling and triggering a broadcast storm. Exposure requires an IP-addressed management interface in the Up state; exploitation degrades performance, drops management connectivity, and can halt device responsiveness.
The record
- CVE
- CVE-2025-20340
- Published
- Sep 10, 2025
- Updated
- Sep 10, 2025
- Vendor
- ClamAV
- Product
- Cisco IOS XR Software
- Classifications
- CWE-400, T1498.001
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 10, 2025CVE publishedPublication date reported by the CVE source.
- Sep 10, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=24.1.1
- Affected versionversion=24.1.2
- Affected versionversion=24.2.1
- Affected versionversion=24.2.11
- Affected versionversion=24.2.2
- Affected versionversion=24.2.20
- Affected versionversion=24.3.1
- Affected versionversion=24.3.2
- Affected versionversion=24.3.20
- Affected versionversion=24.3.30
- Affected versionversion=24.4.1
- Affected versionversion=24.4.10
- Affected versionversion=24.4.15
- Affected versionversion=24.4.2
- Affected versionversion=24.4.30
- Affected versionversion=25.1.1
- Affected versionversion=6.5.1
- Affected versionversion=6.5.15
- Affected versionversion=6.5.2
- Affected versionversion=6.5.25
- Affected versionversion=6.5.26
- Affected versionversion=6.5.28
- Affected versionversion=6.5.29
- Affected versionversion=6.5.3
- Affected versionversion=6.5.31
- Affected versionversion=6.5.32
- Affected versionversion=6.5.33
- Affected versionversion=6.5.35
- Affected versionversion=6.5.351
- Affected versionversion=6.5.352
- Affected versionversion=6.5.90
- Affected versionversion=6.5.92
- Affected versionversion=6.5.93
- Affected versionversion=6.6.1
- Affected versionversion=6.6.11
- Affected versionversion=6.6.12
- Affected versionversion=6.6.2
- Affected versionversion=6.6.25
- Affected versionversion=6.6.3
- Affected versionversion=6.6.4
- Affected versionversion=6.7.1
- Affected versionversion=6.7.2
- Affected versionversion=6.7.3
- Affected versionversion=6.7.35
- Affected versionversion=6.7.4
- Affected versionversion=6.8.1
- Affected versionversion=6.8.2
- Affected versionversion=6.9.1
- Affected versionversion=6.9.2
- Affected versionversion=7.0.0
- Affected versionversion=7.0.1
- Affected versionversion=7.0.11
- Affected versionversion=7.0.12
- Affected versionversion=7.0.14
- Affected versionversion=7.0.2
- Affected versionversion=7.0.90
- Affected versionversion=7.10.1
- Affected versionversion=7.10.2
- Affected versionversion=7.1.1
- Affected versionversion=7.11.1
- Affected versionversion=7.11.2
- Affected versionversion=7.11.21
- Affected versionversion=7.1.15
- Affected versionversion=7.1.2
- Affected versionversion=7.1.25
- Affected versionversion=7.1.3
- Affected versionversion=7.2.0
- Affected versionversion=7.2.1
- Affected versionversion=7.2.12
- Affected versionversion=7.2.2
- Affected versionversion=7.3.1
- Affected versionversion=7.3.15
- Affected versionversion=7.3.16
- Affected versionversion=7.3.2
- Affected versionversion=7.3.27
- Affected versionversion=7.3.3
- Affected versionversion=7.3.4
- Affected versionversion=7.3.5
- Affected versionversion=7.3.6
- Affected versionversion=7.4.1
- Affected versionversion=7.4.15
- Affected versionversion=7.4.16
- Affected versionversion=7.4.2
- Affected versionversion=7.5.1
- Affected versionversion=7.5.12
- Affected versionversion=7.5.2
- Affected versionversion=7.5.3
- Affected versionversion=7.5.4
- Affected versionversion=7.5.5
- Affected versionversion=7.5.52
- Affected versionversion=7.6.1
- Affected versionversion=7.6.15
- Affected versionversion=7.6.2
- Affected versionversion=7.6.3
- Affected versionversion=7.7.1
- Affected versionversion=7.7.2
- Affected versionversion=7.7.21
- Affected versionversion=7.8.1
- Affected versionversion=7.8.12
- Affected versionversion=7.8.2
- Affected versionversion=7.8.22
- Affected versionversion=7.8.23
- Affected versionversion=7.9.1
- Affected versionversion=7.9.2
- Affected versionversion=7.9.21
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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