Cisco IOS Software Network Address Translation Denial-of-Service Vulnerability
A vulnerability in the implementation of Network Address Translation (NAT) functionality in Cisco IOS could allow an unauthenticated, remote attacker to cause a denial of service.
- Vendor
- Cisco
- Product
- IOS software
- CVSS
- 7.5
- EPSS (exploit probability)
- 7.1%
- Status
- kev
- CISA patch-by (BOD 22-01)
- Added to KEV
Is CVE-2017-12231 being exploited?
Yes. CISA added CVE-2017-12231 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 7.1% (scored October 14, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ — ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-11-13. Full cross-catalog view: /kev-comparison
CVE-2017-12231 timeline
Every event links to its source. Catalog dates are each catalog's own; day offsets count from NVD publication. Data: JSON
What to do
CISA required actionApply updates per vendor instructions.
US federal civilian agencies must remediate by (21 days after listing) under BOD 22-01. Everyone else: that deadline is a sensible upper bound, not a target. Vendor guidance and the NVD record are linked under Source above.
Other Cisco IOS CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2008-4128 Cisco IOS 12.4 HTTP admin CSRF on the 871 Integrated Services Routerwrite-up | [ MEDIUM ] | 4.3 | 33.9% | |
| CVE-2004-1464 Cisco IOS Denial-of-Service Vulnerability | [ MEDIUM ] | 5.9 | 4.8% | |
| CVE-2018-0180 Cisco IOS Software Denial-of-Service Vulnerability | [ MEDIUM ] | 5.9 | 4.9% | |
| CVE-2018-0179 Cisco IOS Software Denial-of-Service Vulnerability | [ MEDIUM ] | 5.9 | 4.9% | |
| CVE-2018-0161 Cisco IOS Software Resource Management Errors Vulnerability | [ MEDIUM ] | 6.3 | 4.1% | |
| CVE-2018-0154 Cisco IOS Software Integrated Services Module for VPN Denial-of-Service Vulnerability | [ HIGH ] | 7.5 | 7.1% | |
| CVE-2017-6744 Cisco IOS Software SNMP Remote Code Execution Vulnerability | [ HIGH ] | 8.8 | 7.3% | |
| CVE-2017-12235 Cisco IOS Software for Cisco Industrial Ethernet Switches PROFINET Denial-of-Service Vulnerability | [ HIGH ] | 7.5 | 7.1% |