Internet Explorer in Microsoft Windows 7 SP1, Windows Server 2008 and R2 SP1, Windows 8.1 and Windows RT 8.1, Windows Server 2012 and R2, Windows 10 Gold, 1511, 1607, 1703, 1709, and Windows Server 2016 allows remote code execution, due to how the scripting engine handles objects in memory, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2018-0834, CVE-2018-0835, CVE-2018-0836, CVE-2018-0837, CVE-2018-0838, CVE-2018-0840, CVE-2018-0856, CVE-2018-0857, CVE-2018-0858, CVE-2018-0859, CVE-2018-0860, and CVE-2018-0861.
CVE-2018-0866
Score elevated to 7.9 because EPSS predicts 44% probability of exploitation within the next 30 days (top 1.4% of all CVEs). NVD baseline CVSS 7.5 retained for reference. Confidence: see factors.
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.5
- EG Score
- 7.9(high)
- EG Risk
- 66(Track)EG Risk 66/100SSVC: Track
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 computedSeverity79% × 45%Exploitation65% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 98.6%
- KEV
- Not listed
Published
February 15, 2018
Last Modified
November 21, 2024
References (10)
- secure@microsofthttp://www.securityfocus.com/bid/103032
- secure@microsofthttp://www.securitytracker.com/id/1040369
- secure@microsofthttp://www.securitytracker.com/id/1040372
- secure@microsofthttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-0866
- secure@microsofthttps://www.exploit-db.com/exploits/44153/
- af854a3a-2127-422b-91ae-364da2661108http://www.securityfocus.com/bid/103032
- af854a3a-2127-422b-91ae-364da2661108http://www.securitytracker.com/id/1040369
- af854a3a-2127-422b-91ae-364da2661108http://www.securitytracker.com/id/1040372
- af854a3a-2127-422b-91ae-364da2661108https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-0866
- af854a3a-2127-422b-91ae-364da2661108https://www.exploit-db.com/exploits/44153/
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(1)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
Data Freshness Timeline
(refreshed 10× in last 7d / 32× 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.
- 2026-07-23 14:15 UTCEPSS rescore
- 2026-07-23 01:31 UTCEG score recompute▲ 0.40
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- 2026-05-28 11:32 UTCEG score recompute
- 2026-05-28 11:32 UTCVendor advisory
- 2026-05-28 11:32 UTCGHSA enrichment
- 2026-05-27 13:38 UTCEPSS rescore
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- 2026-05-25 18:16 UTCOSV refresh
Publicly available exploits
(1 reference)Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.
- Exploit-DBEDB-44153✓ verifiedFirst seen Feb 20, 2018
Microsoft Internet Explorer 11 - 'Js::RegexHelper::RegexReplace' Use-After-Free
Open source ↗
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Same CWE
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- CVE-2010-4398NVD 7.8EG 9.0 KEVEPSS 95%HIGH
- CVE-2010-3333NVD 7.8EG 9.0 KEVEPSS 100%HIGH
- CVE-2010-2883NVD 7.3EG 9.0 KEVEPSS 100%HIGH
- CVE-2010-1297NVD 7.8EG 9.0 KEVEPSS 100%HIGH
- CVE-2009-3953NVD 8.8EG 9.0 KEVEPSS 100%HIGH
- CVE-2009-3129NVD 7.8EG 9.0 KEVEPSS 100%HIGH
Frequently asked(5)
What is CVE-2018-0866?
When was CVE-2018-0866 disclosed?
Is CVE-2018-0866 actively exploited?
What is the CVSS score of CVE-2018-0866?
How do I remediate CVE-2018-0866?
Dependency Blast Radius
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