CVE-2017-12231

CRITICALNVD 7.59.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2022-03-03), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 7.5 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 3 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictMitigate nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 7.1%CVSS: 7.5Exploit: cisa kev · ssvc activeExposed services: Not assessed

No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.

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.

CVSS v3
7.5
EG Score
9.0CRITICALhigh confidence
EG Risk
96
EG Risk 96/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation100% × 40%
Automatability100% × 15%
CISA SSVC: Attend at low or medium mission impact; Act at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation sooner than your standard update timelines at low or medium mission impact and as soon as possible at high, and watch the vendor's advisory for the fix.
EPSS PROB
7.1%
EPSS %ILE
94th
KEV
⚠ Exploited

CISA SSVCAttend at low or medium mission impact; Act at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation sooner than your standard update timelines at low or medium mission impact and as soon as possible at high, and watch the vendor's advisory for the fix.

Exploitation active (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 29, 2017

Last Modified

June 17, 2026

Advisory Details (4)

Auto-updated May 19, 2026
⚠️ Active exploitation confirmed. No fix on record yet. Sources: cisa.
cisa🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-12231
generic🔴 Active Exploitation

Cisco IOS Software Network Address Translation Denial of Service Vulnerability

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-nat
generic
http://www.securitytracker.com/id/1039449
generic
http://www.securityfocus.com/bid/101039

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 54× in last 7d / 241× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 1,064 total refreshes for this CVE.

  1. 2026-10-10 07:30 UTCGHSA enrichment
  2. 2026-10-10 03:27 UTCGHSA enrichment
  3. 2026-10-09 23:25 UTCEG score recompute
  4. 2026-10-09 23:25 UTCGHSA enrichment
  5. 2026-10-09 20:02 UTCEPSS rescore
  6. 2026-10-09 19:23 UTCGHSA enrichment
  7. 2026-10-09 15:20 UTCGHSA enrichment
  8. 2026-10-09 11:18 UTCGHSA enrichment
  9. 2026-10-09 07:14 UTCGHSA enrichment
  10. 2026-10-09 03:12 UTCGHSA enrichment
  11. 2026-10-08 23:10 UTCGHSA enrichment
  12. 2026-10-08 19:09 UTCEG score recompute
  13. 2026-10-08 19:08 UTCGHSA enrichment
  14. 2026-10-08 16:35 UTCEPSS rescore
  15. 2026-10-08 15:07 UTCGHSA enrichment
  16. 2026-10-08 11:04 UTCGHSA enrichment
  17. 2026-10-08 07:03 UTCGHSA enrichment
  18. 2026-10-08 03:02 UTCEG score recompute
  19. 2026-10-08 03:02 UTCGHSA enrichment
  20. 2026-10-07 23:41 UTCEPSS rescore
  21. 2026-10-07 23:00 UTCGHSA enrichment
  22. 2026-10-07 18:58 UTCGHSA enrichment
  23. 2026-10-07 14:57 UTCGHSA enrichment
  24. 2026-10-07 10:55 UTCGHSA enrichment
  25. 2026-10-07 06:53 UTCGHSA enrichment
Show 75 more
  1. 2026-10-07 02:51 UTCGHSA enrichment
  2. 2026-10-06 22:49 UTCGHSA enrichment
  3. 2026-10-06 18:47 UTCEG score recompute
  4. 2026-10-06 18:47 UTCGHSA enrichment
  5. 2026-10-06 15:11 UTCEPSS rescore
  6. 2026-10-06 14:45 UTCGHSA enrichment
  7. 2026-10-06 10:43 UTCGHSA enrichment
  8. 2026-10-06 06:41 UTCGHSA enrichment
  9. 2026-10-06 02:38 UTCGHSA enrichment
  10. 2026-10-05 22:36 UTCGHSA enrichment
  11. 2026-10-05 18:32 UTCEG score recompute
  12. 2026-10-05 18:32 UTCGHSA enrichment
  13. 2026-10-05 17:38 UTCEPSS rescore
  14. 2026-10-05 14:31 UTCGHSA enrichment
  15. 2026-10-05 10:29 UTCGHSA enrichment
  16. 2026-10-05 06:28 UTCGHSA enrichment
  17. 2026-10-05 02:26 UTCGHSA enrichment
  18. 2026-10-04 22:24 UTCGHSA enrichment
  19. 2026-10-04 18:22 UTCGHSA enrichment
  20. 2026-10-04 14:18 UTCGHSA enrichment
  21. 2026-10-04 10:15 UTCGHSA enrichment
  22. 2026-10-04 06:13 UTCGHSA enrichment
  23. 2026-10-04 02:11 UTCGHSA enrichment
  24. 2026-10-03 22:10 UTCGHSA enrichment
  25. 2026-10-03 18:08 UTCEG score recompute
  26. 2026-10-03 18:08 UTCGHSA enrichment
  27. 2026-10-03 14:21 UTCEPSS rescore
  28. 2026-10-03 14:04 UTCGHSA enrichment
  29. 2026-10-03 10:02 UTCGHSA enrichment
  30. 2026-10-03 06:00 UTCGHSA enrichment
  31. 2026-10-03 01:58 UTCGHSA enrichment
  32. 2026-10-02 21:57 UTCGHSA enrichment
  33. 2026-10-02 17:55 UTCEG score recompute
  34. 2026-10-02 17:55 UTCGHSA enrichment
  35. 2026-10-02 13:54 UTCGHSA enrichment
  36. 2026-10-02 09:51 UTCGHSA enrichment
  37. 2026-10-02 05:50 UTCGHSA enrichment
  38. 2026-10-02 01:48 UTCGHSA enrichment
  39. 2026-10-01 21:46 UTCEG score recompute
  40. 2026-10-01 21:45 UTCGHSA enrichment
  41. 2026-10-01 17:42 UTCGHSA enrichment
  42. 2026-10-01 13:38 UTCGHSA enrichment
  43. 2026-10-01 09:37 UTCGHSA enrichment
  44. 2026-10-01 05:35 UTCGHSA enrichment
  45. 2026-10-01 01:33 UTCGHSA enrichment
  46. 2026-09-30 21:32 UTCGHSA enrichment
  47. 2026-09-30 17:30 UTCEG score recompute
  48. 2026-09-30 17:30 UTCGHSA enrichment
  49. 2026-09-30 14:58 UTCEPSS rescore
  50. 2026-09-30 13:28 UTCGHSA enrichment
  51. 2026-09-30 09:27 UTCGHSA enrichment
  52. 2026-09-30 05:24 UTCGHSA enrichment
  53. 2026-09-30 01:22 UTCGHSA enrichment
  54. 2026-09-29 21:19 UTCGHSA enrichment
  55. 2026-09-29 17:13 UTCEG score recompute
  56. 2026-09-29 17:13 UTCGHSA enrichment
  57. 2026-09-29 13:10 UTCGHSA enrichment
  58. 2026-09-29 09:05 UTCGHSA enrichment
  59. 2026-09-29 05:02 UTCGHSA enrichment
  60. 2026-09-29 01:00 UTCEG score recompute
  61. 2026-09-29 01:00 UTCGHSA enrichment
  62. 2026-09-28 20:59 UTCGHSA enrichment
  63. 2026-09-28 16:57 UTCEG score recompute
  64. 2026-09-28 16:57 UTCGHSA enrichment
  65. 2026-09-28 13:45 UTCEPSS rescore
  66. 2026-09-28 12:53 UTCGHSA enrichment
  67. 2026-09-28 08:51 UTCGHSA enrichment
  68. 2026-09-28 04:50 UTCGHSA enrichment
  69. 2026-09-28 00:48 UTCGHSA enrichment
  70. 2026-09-27 21:51 UTCCISA KEV update
  71. 2026-09-27 20:46 UTCGHSA enrichment
  72. 2026-09-27 16:44 UTCEG score recompute
  73. 2026-09-27 16:44 UTCGHSA enrichment
  74. 2026-09-27 13:40 UTCEPSS rescore
  75. 2026-09-27 12:42 UTCGHSA enrichment

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Frequently asked(6)

What is CVE-2017-12231?
CVE-2017-12231 is a critical vulnerability published on September 29, 2017. 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…
When was CVE-2017-12231 disclosed?
CVE-2017-12231 was first published on September 29, 2017, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2017-12231 actively exploited?
Yes. CISA added CVE-2017-12231 to the Known Exploited Vulnerabilities catalog on March 3, 2022, affecting Cisco IOS software. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate attention. No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation, and watch the vendor's advisory for the fix.
What is the CVSS score of CVE-2017-12231?
CVE-2017-12231 has a CVSS v3 base score of 7.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0 (CRITICAL).
Which products are affected by CVE-2017-12231?
CVE-2017-12231 affects Cisco IOS software.
How do I remediate CVE-2017-12231?
No fix for CVE-2017-12231 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix.

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