A vulnerability in the implementation of Internet Key Exchange Version 1 (IKEv1) functionality in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to improper validation of specific IKEv1 packets. An attacker could exploit this vulnerability by sending crafted IKEv1 packets to an affected device during an IKE negotiation. A successful exploit could allow the attacker to cause an affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCuj73916.
CVE-2018-0159
“▲” beside the score: it is higher than NVD's CVSS score.
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. The 9.0 is the floor for confirmed exploitation, not an impact rating: this CVE's impact severity (EG Severity) is CVSS 7.5 HIGH under GitHub Security Advisory CVSS. Confidence: HIGH.
- Actively exploited in the wild (CISA-KEV) — the reason this is sooner than the SSVC decision on this page at low or medium mission impact
No fix has been recorded since the CVE record was published in 2018 — use a compensating control (WAF / firewall / segmentation) and check the vendor's advisory.
- CVSS v3
- 7.5
- EG Score
- 9.0CRITICALhigh confidence
- EG Risk
- 89EG Risk 89/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity75% × 45%Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation100% × 40%Fixed at 100% for a CISA KEV listing: EchelonGraph's rule.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Attend at low or medium mission impact; Act at high (mission-essential systems).Exploitation active (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: No fix has been recorded since the CVE record was published in 2018. 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 check the vendor's advisory for a fix. - EPSS PROB
- 6.9%
- EPSS %ILE
- 94th
- KEV
- ⚠ Exploited
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (9.0): severity, escalated by confirmed exploitation. This CVE's 9.0 is the CISA KEV floor for confirmed exploitation, not an impact rating: its impact severity (EG Severity) is CVSS 7.5 HIGH.
- EG Severity
- 7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 6.9% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-23). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- CISA KEV and EG-KEV Tier 1 (exploited in the wild)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Attend at medium mission impactAttend at low or medium mission impact; Act at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 14 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Attend at low or medium mission impact; Act at high (mission-essential systems).
No fix has been recorded since the CVE record was published in 2018. 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 check the vendor's advisory for a fix.
Exploitation active (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)3 days if the affected system is publicly exposed; 14 days if it is not.
In CISA KEV yes (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
CISA required action“Apply updates per vendor instructions.”
Quoted verbatim from CISA's Known Exploited Vulnerabilities catalog. CISA directs it at US federal civilian executive branch agencies under Binding Operational Directive (BOD) 26-04, which replaced BOD 22-01 on 10 June 2026; it is not EchelonGraph's advice. CISA's notes: https://nvd.nist.gov/vuln/detail/CVE-2018-0159
Published
March 28, 2018
Last Modified
January 14, 2026
Advisory Details (4)
Auto-updated Oct 20, 2026Known 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-2018-0159Cisco IOS and IOS XE Software Internet Key Exchange Version 1 Denial of Service Vulnerability
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-ike-dosWeakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 21× in last 7d / 191× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 99 of 1,140 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 100 is merged into the row it repeats. The 1,041 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-10-23 16:54 UTCEG score recompute
- 2026-10-23 16:54 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-23 16:27 UTCEPSS rescoreEPSS 6.9% · 94th percentile
- 2026-10-22 16:27 UTCEPSS rescoreEPSS 6.9% · 94th percentile
- 2026-10-22 16:11 UTCEG score recompute
- 2026-10-22 16:11 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-21 16:27 UTCEPSS rescoreEPSS 6.9% · 94th percentile
- 2026-10-21 15:26 UTCEG score recompute
- 2026-10-21 15:26 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-20 16:27 UTCEPSS rescoreEPSS 6.9% · 94th percentile
- 2026-10-20 14:43 UTCEG score recompute
- 2026-10-20 14:43 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-19 16:26 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-19 14:01 UTCEG score recompute
- 2026-10-19 14:00 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-18 16:27 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-18 13:16 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-18 10:25 UTCEG score recompute
- 2026-10-17 16:27 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-17 12:32 UTCEG score recompute
- 2026-10-17 12:32 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-16 16:29 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-16 11:49 UTCEG score recompute
- 2026-10-16 11:49 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-15 16:27 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
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- 2026-10-15 11:06 UTCEG score recompute
- 2026-10-15 11:05 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-14 16:27 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-14 10:20 UTCEG score recompute
- 2026-10-14 10:20 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-13 16:27 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-13 09:37 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-12 20:23 UTCEG score recompute
- 2026-10-12 16:28 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-12 08:52 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-12 05:00 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-12 01:07 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-11 21:13 UTCEG score recompute
- 2026-10-11 21:13 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-11 17:19 UTCEG score recompute
- 2026-10-11 17:18 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-11 13:41 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-11 13:24 UTCEG score recompute
- 2026-10-11 13:24 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-11 09:31 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-11 05:36 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-11 01:44 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-10 21:50 UTCEG score recompute
- 2026-10-10 21:50 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-10 19:55 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-10 17:58 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-10 14:04 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-10 10:12 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-10 06:20 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-10 02:27 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-09 22:36 UTCEG score recompute
- 2026-10-09 22:36 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-09 20:02 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-09 18:43 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-09 14:51 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-09 10:57 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-09 07:05 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-09 03:12 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-08 23:20 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-08 19:28 UTCEG score recompute
- 2026-10-08 19:28 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-08 16:36 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-08 15:35 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-08 11:43 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-08 07:51 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-08 03:59 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-08 00:06 UTCEG score recompute
- 2026-10-08 00:06 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-07 23:41 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-07 20:14 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-07 16:22 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-07 12:29 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-07 08:37 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-07 04:45 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-07 00:53 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-06 21:00 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-06 17:06 UTCEG score recompute
- 2026-10-06 17:06 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-06 15:12 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-06 13:14 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-06 09:22 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-06 05:30 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-06 01:34 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-05 21:42 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-05 17:48 UTCEG score recompute
- 2026-10-05 17:48 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-05 17:39 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-05 13:56 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-05 10:04 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-05 06:12 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-05 02:20 UTCEG score recompute
- 2026-10-05 02:20 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-04 23:18 UTCEPSS rescoreEPSS 6.9% · 93rd percentile
- 2026-10-04 22:28 UTCGHSA enrichmentGHSA-p7j7-5cqq-j6m7 · GitHub severity HIGH · GitHub CVSS 7.5
Related CVEs(same CWE)
Same CWE
10 shownCWE-20
- CVE-2018-0158NVD 8.6EG 9.0 KEVEPSS p94CRITICAL
- CVE-2018-0156NVD 7.5EG 9.0 KEVEPSS p95CRITICAL
- CVE-2018-0171EG 9.8 KEVEPSS p100CRITICAL
- CVE-2018-0172NVD 8.6EG 9.0 KEVEPSS p95CRITICAL
- CVE-2018-0173NVD 8.6EG 9.0 KEVEPSS p95CRITICAL
- CVE-2018-0174NVD 8.6EG 9.0 KEVEPSS p95CRITICAL
- CVE-2018-0196EG 4.9MEDIUM
- CVE-2018-1000136EG 8.1EPSS p92HIGH
- CVE-2018-1000156EG 7.8EPSS p93HIGH
- CVE-2018-0017EG 7.5HIGH
Frequently asked(6)
What is CVE-2018-0159?
When was CVE-2018-0159 made public?
Is CVE-2018-0159 actively exploited?
What is the CVSS score of CVE-2018-0159?
Which products are affected by CVE-2018-0159?
How do I remediate CVE-2018-0159?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2018-0159
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