A vulnerability in the implementation of the PROFINET Discovery and Configuration Protocol (PN-DCP) for Cisco IOS 12.2 through 15.6 could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to the improper parsing of ingress PN-DCP Identify Request packets destined to an affected device. An attacker could exploit this vulnerability by sending a crafted PN-DCP Identify Request packet to an affected device and then continuing to send normal PN-DCP Identify Request packets to the device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. This vulnerability affects Cisco devices that are configured to process PROFINET messages. Beginning with Cisco IOS Software Release 12.2(52)SE, PROFINET is enabled by default on all the base switch module and expansion-unit Ethernet ports. Cisco Bug IDs: CSCuz47179.
Conclusion & alert: CVE-2017-12235 is rated Critical Active Threat (85.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 5.16%). Core evidence: CISA KEV confirms active exploitation (added 2022-03-03) affecting Cisco / IOS software. a weakness (CWE-20) Unauthenticated remote administrative access may be possible. Mandatory action: The CISA remediation deadline has passed—treat as an emergency patch priority.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
: Cisco IOS Software for Cisco Industrial Ethernet Switches PROFINET 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 | 2026-05-22 | 6.54% | 5.16% | -1.39% |
| 2 | 2026-04-22 | 4.93% | 6.54% | +1.62% |
| 3 | 2025-12-19 | — | 4.93% | — |
Full EPSS history (16 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | [email protected] |
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
| 7.8 | 2.0 | HIGH |
|
10.0 | 6.9 | [email protected] |
| URL | Tags |
|---|---|
| http://www.securityfocus.com/bid/101043 | Broken Link Third Party Advisory VDB Entry |
| http://www.securitytracker.com/id/1039451 | Broken Link Third Party Advisory VDB Entry |
| https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-profinet | Vendor Advisory |
| https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-12235 | US Government Resource |