Egress-port service interruption via stuck FIFO queue
Published Sep 24, 2025 · Updated Sep 30, 2025
Improper Ethernet-frame handling in Cisco IOS XE Software allows attackers to block an egress port with crafted frames. Crafted frames can leave the affected port's egress FIFO queue stuck, causing the port to drop all outbound traffic continuously. Exposure requires an affected Catalyst 9000-family platform running a vulnerable release with a trunk, Cisco TrustSec, or MACsec-enabled port and adjacent access to send Ethernet frames through the switch.
Summary
What happened
Improper Ethernet-frame handling in Cisco IOS XE Software allows attackers to block an egress port with crafted frames. Crafted frames can leave the affected port's egress FIFO queue stuck, causing the port to drop all outbound traffic continuously. Exposure requires an affected Catalyst 9000-family platform running a vulnerable release with a trunk, Cisco TrustSec, or MACsec-enabled port and adjacent access to send Ethernet frames through the switch.
The record
- CVE
- CVE-2025-20311
- Published
- Sep 24, 2025
- Updated
- Sep 30, 2025
- Vendor
- ClamAV
- Product
- Cisco IOS XE Software
- Classifications
- CWE-19, T1499.004
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 24, 2025CVE publishedPublication date reported by the CVE source.
- Sep 30, 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=16.10.1
- Affected versionversion=16.10.1e
- Affected versionversion=16.10.1s
- Affected versionversion=16.11.1
- Affected versionversion=16.11.1b
- Affected versionversion=16.11.1s
- Affected versionversion=16.12.1
- Affected versionversion=16.12.14
- Affected versionversion=16.12.1c
- Affected versionversion=16.12.1s
- Affected versionversion=16.12.2
- Affected versionversion=16.12.2s
- Affected versionversion=16.12.3
- Affected versionversion=16.12.3a
- Affected versionversion=16.12.3s
- Affected versionversion=16.12.4
- Affected versionversion=16.12.4a
- Affected versionversion=16.12.5
- Affected versionversion=16.12.5b
- Affected versionversion=16.12.6
- Affected versionversion=16.12.6a
- Affected versionversion=16.12.7
- Affected versionversion=16.12.8
- Affected versionversion=16.6.1
- Affected versionversion=16.6.10
- Affected versionversion=16.6.2
- Affected versionversion=16.6.3
- Affected versionversion=16.6.4
- Affected versionversion=16.6.4a
- Affected versionversion=16.6.5
- Affected versionversion=16.6.6
- Affected versionversion=16.6.7
- Affected versionversion=16.6.8
- Affected versionversion=16.6.9
- Affected versionversion=16.7.1
- Affected versionversion=16.8.1
- Affected versionversion=16.8.1a
- Affected versionversion=16.8.1s
- Affected versionversion=16.9.1
- Affected versionversion=16.9.1s
- Affected versionversion=16.9.2
- Affected versionversion=16.9.3
- Affected versionversion=16.9.4
- Affected versionversion=16.9.5
- Affected versionversion=16.9.6
- Affected versionversion=16.9.7
- Affected versionversion=16.9.8
- Affected versionversion=17.10.1
- Affected versionversion=17.10.1b
- Affected versionversion=17.1.1
- Affected versionversion=17.11.1
- Affected versionversion=17.11.99SW
- Affected versionversion=17.1.1s
- Affected versionversion=17.1.1t
- Affected versionversion=17.12.1
- Affected versionversion=17.12.1z3
- Affected versionversion=17.12.2
- Affected versionversion=17.12.3
- Affected versionversion=17.12.4
- Affected versionversion=17.1.3
- Affected versionversion=17.13.1
- Affected versionversion=17.14.1
- Affected versionversion=17.15.1
- Affected versionversion=17.15.2
- Affected versionversion=17.15.2a
- Affected versionversion=17.15.2b
- Affected versionversion=17.16.1
- Affected versionversion=17.2.1
- Affected versionversion=17.2.1a
- Affected versionversion=17.3.1
- Affected versionversion=17.3.2
- Affected versionversion=17.3.2a
- Affected versionversion=17.3.3
- Affected versionversion=17.3.4
- Affected versionversion=17.3.4b
- Affected versionversion=17.3.5
- Affected versionversion=17.3.6
- Affected versionversion=17.3.7
- Affected versionversion=17.3.8
- Affected versionversion=17.3.8a
- Affected versionversion=17.4.1
- Affected versionversion=17.5.1
- Affected versionversion=17.6.1
- Affected versionversion=17.6.1y
- Affected versionversion=17.6.2
- Affected versionversion=17.6.3
- Affected versionversion=17.6.4
- Affected versionversion=17.6.5
- Affected versionversion=17.6.5a
- Affected versionversion=17.6.6
- Affected versionversion=17.6.6a
- Affected versionversion=17.6.7
- Affected versionversion=17.6.8
- Affected versionversion=17.7.1
- Affected versionversion=17.8.1
- Affected versionversion=17.9.1
- Affected versionversion=17.9.2
- Affected versionversion=17.9.3
- Affected versionversion=17.9.4
- Affected versionversion=17.9.4a
- Affected versionversion=17.9.5
- Affected versionversion=17.9.6
- Affected versionversion=17.9.6a
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.
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
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Your stack
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