Medium 6.5Known exploited (CISA KEV)Published Sep 28, 2017

CVE-2017-12232A vulnerability in the implementation of a protocol in Cisco Integrated Services Routers Generation 2 (ISR G2) Routers running Cisco IOS 15.0 through 15.6 could allow an unauthenticated, adjacent att…

Updated under an hour ago (2026-10-19 06:10 UTC)

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It affects cisco ios. Add what you run to find out whether that includes you.

CISA lists it as known exploited since Mar 3, 2022; federal agencies had to remediate by Mar 24, 2022. Treat that date as your deadline.

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Exploited in the last 30 days

A vulnerability in the implementation of a protocol in Cisco Integrated Services Routers Generation 2 (ISR G2) Routers running Cisco IOS 15.0 through 15.6 could allow an unauthenticated, adjacent attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to a misclassification of Ethernet frames. An attacker could exploit this vulnerability by sending a crafted Ethernet frame to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCvc03809.

CVSS: 6.5 MEDIUM (v3.1, CISA ADP)CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-399
Known exploited: Added to CISA KEV Mar 3, 2022; federal remediation due Mar 24, 2022Apply updates per vendor instructions.
EPSS (exploitation in the next 30 days): 2.15% (percentile 82)
Assigned by: cisco
NVD analysis: Analyzed
Record last updated: Jan 12, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

cisco ios cisco:ios	from 15.0 through 15.6	NVD

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-rbip-dosx-refsource-confirm, vendor-advisory
http://www.securitytracker.com/id/1039452vdb-entry, x-refsource-sectrack, broken-link, third-party-advisory
http://www.securityfocus.com/bid/101044vdb-entry, x-refsource-bid, broken-link, third-party-advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-12232us-government-resource

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.