CVE-2025-20311
published 2025-09-24CVE-2025-20311: A vulnerability in the handling of certain Ethernet frames in Cisco IOS XE Software for Catalyst 9000 Series Switches could allow an unauthenticated, adjacent…
PriorityP338high7.4CVSS 3.1
AVAACLPRNUINSCCNINAH
EPSS
0.19%
8.6th percentile
A vulnerability in the handling of certain Ethernet frames in Cisco IOS XE Software for Catalyst 9000 Series Switches could allow an unauthenticated, adjacent attacker to cause an egress port to become blocked and drop all outbound traffic.
This vulnerability is due to improper handling of crafted Ethernet frames. An attacker could exploit this vulnerability by sending crafted Ethernet frames through an affected switch. A successful exploit could allow the attacker to cause the egress port to which the crafted frame is forwarded to start dropping all frames, resulting in a denial of service (DoS) condition.
Affected
104 ranges· showing 25
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CVSS provenance
nvdv3.17.4HIGHCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
vendor_cisco7.4HIGH
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Cisco
Cisco IOS XE Software for Catalyst 9000 Series Switches Denial of Service Vulnerability
vendor_cisco·2025-09-24·CVSS 7.4
CVE-2025-20311 [HIGH] CWE-19 Cisco IOS XE Software for Catalyst 9000 Series Switches Denial of Service Vulnerability
Cisco IOS XE Software for Catalyst 9000 Series Switches Denial of Service Vulnerability
A vulnerability in the handling of certain Ethernet frames in Cisco IOS XE Software for Catalyst 9000 Series Switches could allow an unauthenticated, adjacent attacker to cause an egress port to become blocked and drop all outbound traffic.
This vulnerability is due to improper handling of crafted Ethernet frames. An attacker could exploit this vulnerability by sending crafted Ethernet frames through an affected switch. A successful exploit could allow the attacker to cause the egress port to which the crafted frame is forwarded to start dropping all frames, resulting in a denial of service (DoS) condition.
Cisco has released software updates that address this vulnerability. There are no workarounds
Cisco
Cisco IOS XE Software for Catalyst 9000 Series Switches Denial of Service Vulnerability
vendor_cisco·CVSS 3.1
CVE-2025-20311 Cisco IOS XE Software for Catalyst 9000 Series Switches Denial of Service Vulnerability
CVE-2025-20311: Cisco IOS XE Software for Catalyst 9000 Series Switches Denial of Service Vulnerability
A vulnerability in the handling of certain Ethernet frames in Cisco IOS XE Software for Catalyst 9000 Series Switches could allow an unauthenticated, adjacent attacker to cause an egress port to become blocked and drop all outbound traffic. This vulnerability is due to improper handling of crafted Ethernet frames. An attacker could exploit this vulnerability by sending crafted Ethernet frames through an affected switch. A successful exploit could allow the attacker to cause the egress port to which the crafted frame is forwarded to start dropping all frames, resulting in a denial of service (DoS) condition. Cisco has released software updates that address this vulnerability. There are no
GHSA
GHSA-pr4q-4px5-72j6: A vulnerability in the handling of certain Ethernet frames in Cisco IOS XE Software for Catalyst 9000 Series Switches could allow an unauthenticated,
ghsa_unreviewed·2025-09-24
CVE-2025-20311 [HIGH] GHSA-pr4q-4px5-72j6: A vulnerability in the handling of certain Ethernet frames in Cisco IOS XE Software for Catalyst 9000 Series Switches could allow an unauthenticated,
A vulnerability in the handling of certain Ethernet frames in Cisco IOS XE Software for Catalyst 9000 Series Switches could allow an unauthenticated, adjacent attacker to cause an egress port to become blocked and drop all outbound traffic.
This vulnerability is due to improper handling of crafted Ethernet frames. An attacker could exploit this vulnerability by sending crafted Ethernet frames through an affected switch. A successful exploit could allow the attacker to cause the egress port to which the crafted frame is forwarded to start dropping all frames, resulting in a denial of service (DoS) condition.
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2025-09-24
Published