CVE-2018-0173

CRITICALNVD 8.69.0▲
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 8.6 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 4 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 8%CVSS: 8.6Exploit: cisa kev · ssvc activeExposed: 0

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

A vulnerability in the Cisco IOS Software and Cisco IOS XE Software function that restores encapsulated option 82 information in DHCP Version 4 (DHCPv4) packets could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a Relay Reply denial of service (DoS) condition. The vulnerability exists because the affected software performs incomplete input validation of encapsulated option 82 information that it receives in DHCPOFFER messages from DHCPv4 servers. An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device, which the device would then forward to a DHCPv4 server. When the affected software processes the option 82 information that is encapsulated in the response from the server, an error could occur. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCvg62754.

CVSS v3
8.6
EG Score
9.0(high)
EG Risk
81(Attend)
EG Risk 81/100SSVC: Attend

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%
Automatability0% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
8%
EPSS %ILE
94%
KEV
⚠ Exploited

Published

March 28, 2018

Last Modified

January 14, 2026

Advisory Details (4)

Auto-updated Jun 2, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic
http://www.securitytracker.com/id/1040591
generic
http://www.securityfocus.com/bid/103545
generic

[R1] Cisco IOS and IOS XE Multiple Memory Corruption Vulnerabilities - Research Advisory | Tenable®

https://www.tenable.com/security/research/tra-2018-06
generic🔴 Active Exploitation

Cisco IOS and IOS XE Software DHCP Version 4 Relay Reply Denial of Service Vulnerability

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr2

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 53× in last 7d / 225× 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 752 total refreshes for this CVE.

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

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Frequently asked(6)

What is CVE-2018-0173?
CVE-2018-0173 is a critical vulnerability published on March 28, 2018. A vulnerability in the Cisco IOS Software and Cisco IOS XE Software function that restores encapsulated option 82 information in DHCP Version 4 (DHCPv4) packets could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a Relay Reply denial of service (DoS)…
When was CVE-2018-0173 disclosed?
CVE-2018-0173 was first published in the National Vulnerability Database on March 28, 2018, with the most recent update on January 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2018-0173 actively exploited?
Yes. CISA added CVE-2018-0173 to the Known Exploited Vulnerabilities catalog on March 3, 2022, affecting Cisco IOS and IOS XE Software. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2018-0173?
CVE-2018-0173 has a CVSS v3 base score of 8.6 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2018-0173?
CVE-2018-0173 affects Cisco IOS and IOS XE Software. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2018-0173?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2018-0173, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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