A vulnerability in the Secure Sockets Layer (SSL) Virtual Private Network (VPN) Client Certificate Authentication feature for Cisco Adaptive Security Appliance (ASA) could allow an unauthenticated, remote attacker to establish an SSL VPN connection and bypass certain SSL certificate verification steps. The vulnerability is due to incorrect verification of the SSL Client Certificate. An attacker could exploit this vulnerability by connecting to the ASA VPN without a proper private key and certificate pair. A successful exploit could allow the attacker to establish an SSL VPN connection to the ASA when the connection should have been rejected. This vulnerability affects Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) Software that is running on the following Cisco products: 3000 Series Industrial Security Appliances (ISA), ASA 5500 Series Adaptive Security Appliances, ASA 5500-X Series Next-Generation Firewalls, ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers, Adaptive Security Virtual Appliances (ASAv), Firepower 4110 Security Appliances, Firepower 9300 ASA Security Modules. Cisco Bug IDs: CSCvg40155.
CVE-2018-0227
“—” beside the score: it is equal to NVD's CVSS score.
Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2022-05-13. NVD baseline CVSS 7.5; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
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
- 7.5HIGHmedium confidence
- EG Risk
- 50EG Risk 50/100
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.Exploitation2.1% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation none (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 within your standard update timelines at low or medium mission impact and sooner than that at high, and check the vendor's advisory for a fix. - EPSS PROB
- 2.1%
- EPSS %ILE
- 81st
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 2.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-21). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 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)Track at low or medium mission impact; Attend 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 within your standard update timelines at low or medium mission impact and sooner than that at high, and check the vendor's advisory for a fix.
Exploitation none (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)14 days if the affected system is publicly exposed; 60 days if it is not.
In CISA KEV no (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
Published
April 19, 2018
Last Modified
August 11, 2026
Advisory Details (4)
Auto-updated Aug 11, 2026Cisco Adaptive Security Appliance Virtual Private Network SSL Client Certificate Bypass Vulnerability
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180418-asa1Rockwell Automation Allen-Bradley Stratix 5950 | CISA
https://ics-cert.us-cert.gov/advisories/ICSA-18-184-01Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 32× 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 86 of 160 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. 14 repeat rows among the latest 100 are merged into the row they repeat. The 74 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-10-23 16:27 UTCEPSS rescoreEPSS 2.1% · 81st percentile
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- 2026-10-21 23:55 UTCEG score recompute
- 2026-10-21 23:55 UTCGHSA enrichmentGHSA-25vq-3gfh-mvj7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-21 16:27 UTCEPSS rescoreEPSS 2.1% · 81st percentile
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- 2026-10-18 10:25 UTCEG score recompute
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- 2026-09-30 14:59 UTCEPSS rescoreEPSS 2.0% · 80th percentile
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- 2026-08-19 16:59 UTCEPSS rescoreEPSS 2.0% · 79th percentile
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- 2026-08-12 13:46 UTCEPSS rescoreEPSS 2.0% · 79th percentile
- 2026-08-11 20:00 UTCEG score recompute
- 2026-08-11 20:00 UTCGHSA enrichmentGHSA-25vq-3gfh-mvj7 · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-08-09 13:42 UTCEPSS rescoreEPSS 2.0% · 79th percentile
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- 2026-07-23 01:31 UTCEG score recompute
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Frequently asked(5)
What is CVE-2018-0227?
When was CVE-2018-0227 made public?
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What is the CVSS score of CVE-2018-0227?
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Dependency Blast Radius
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