A vulnerability in the Virtual Private LAN Service (VPLS) code of Cisco IOS 15.0 through 15.4 for Cisco Catalyst 6800 Series Switches could allow an unauthenticated, adjacent attacker to cause a C6800-16P10G or C6800-16P10G-XL type line card to crash, resulting in a denial of service (DoS) condition. The vulnerability is due to a memory management issue in the affected software. An attacker could exploit this vulnerability by creating a large number of VPLS-generated MAC entries in the MAC address table of an affected device. A successful exploit could allow the attacker to cause a C6800-16P10G or C6800-16P10G-XL type line card to crash, resulting in a DoS condition. This vulnerability affects Cisco Catalyst 6800 Series Switches that are running a vulnerable release of Cisco IOS Software and have a Cisco C6800-16P10G or C6800-16P10G-XL line card in use with Supervisor Engine 6T. To be vulnerable, the device must also be configured with VPLS and the C6800-16P10G or C6800-16P10G-XL line card needs to be the core-facing MPLS interfaces. Cisco Bug IDs: CSCva61927.
Conclusion & alert: CVE-2017-12238 is rated Active Exploitation (79.5/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.03%). Core evidence: CISA KEV confirms active exploitation (added 2022-03-03) affecting Cisco / Catalyst 6800 Series Switches. a weakness (CWE-399) Unauthenticated remote administrative access may be possible. EPSS rose +1.02% over the last day, indicating growing attacker interest. Mandatory action: The CISA remediation deadline has passed—treat as an emergency patch priority.
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: Cisco Catalyst 6800 Series Switches VPLS Denial-of-Service Vulnerability · CISA KEV detail
: 2022-03-03
: 2022-03-24
: Apply updates per vendor instructions.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 1.01% | 2.03% | +1.02% |
| 2 | 2026-04-22 | 1.15% | 1.01% | -0.14% |
| 3 | 2025-10-22 | — | 1.15% | — |
Full EPSS history (8 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 6.5 | 3.1 | MEDIUM |
|
2.8 | 3.6 | [email protected] |
| 6.5 | 3.1 | MEDIUM |
|
2.8 | 3.6 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
| 3.3 | 2.0 | LOW |
|
6.5 | 2.9 | [email protected] |
| URL | Tags |
|---|---|
| http://www.securityfocus.com/bid/101040 | Broken Link Third Party Advisory VDB Entry |
| http://www.securitytracker.com/id/1039453 | Broken Link Third Party Advisory VDB Entry |
| https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-vpls | Vendor Advisory |
| https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-12238 | US Government Resource |