CVE-2017-12231
A vulnerability in the implementation of Network Address Translation (NAT) functionality in Cisco IOS 12.4 through 15.6 could allow an…
- 7.5HighCVSS base score
- 7.1%Exploitation in 30 daysEPSS · top 5.7% of all CVEs
- YesKnown exploitedin CISA's KEV since 3 Mar 2022
- YesPublic exploitsa reference or SSVC says so
Description
A vulnerability in the implementation of Network Address Translation (NAT) functionality in Cisco IOS 12.4 through 15.6 could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to the improper translation of H.323 messages that use the Registration, Admission, and Status (RAS) protocol and are sent to an affected device via IPv4 packets. An attacker could exploit this vulnerability by sending a crafted H.323 RAS packet through an affected device. A successful exploit could allow the attacker to cause the affected device to crash and reload, resulting in a DoS condition. This vulnerability affects Cisco devices that are configured to use an application layer gateway with NAT (NAT ALG) for H.323 RAS messages. By default, a NAT ALG is enabled for H.323 RAS messages. Cisco Bug IDs: CSCvc57217.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Cisco IOS Software Network Address Translation Denial-of-Service Vulnerability.
- Added
- 3 Mar 2022
- Fix due (US federal)
- 24 Mar 2022
- Used by ransomware
- Not known
Apply updates per vendor instructions.
ENISA's EU Vulnerability Database lists it as exploited, from CISA's KEV, since 3 Mar 2022.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: it is being exploited.
Timeline
ID reserved
By cisco
- 56 days later
· 56 days later
Published
- 4 years later
· 4 years later
Added to CISA KEV
Known exploited in the wild
- 4 years later
· 4 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Analyzed | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 7.1% · top 5.7% of all CVEs (9 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
Cisco IOS
- affected Cisco IOS
References
4
- 1039449 (opens in a new tab)vdb-entryx_refsource_SECTRACKx_transferred
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-nat (opens in a new tab)x_refsource_CONFIRMx_transferred
- 101039 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-12231 (opens in a new tab)government-resource
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2017-3804 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2017-12231)Record last updated .