Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 3.22% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2020
CVE-2020-1064High confidence
MSHTML Engine Remote Code Execution Vulnerability
Microsoft · Internet Explorer 11
7.5HighCVSS 3.1
Within 7 days
Patch availableHigh technical severity; prioritise exposed affected systems while verifying vendor guidance.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:High, unchanged from published severity.unchanged
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Microsoft Internet Explorer 11 and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
High technical severity; prioritise exposed affected systems while verifying vendor guidance.
Patch available01
What, why and how
A remote code execution vulnerability exists in the way that the MSHTML engine improperly validates input. An attacker could execute arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker who successfully exploited the vulnerability could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. In a HTML editing attack scenario, an attacker could trick a user into editing a specially crafted file that is designed to exploit the vulnerability. The security update addresses the vulnerability by modifying how MSHTML engine validates input.
What
A remote code execution vulnerability exists in the way that the MSHTML engine improperly validates input. An attacker could execute arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker who successfully exploited the vulnerability could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. In a HTML editing attack scenario, an attacker could trick a user into editing a specially crafted file that is designed to exploit the vulnerability. The security update addresses the vulnerability by modifying how MSHTML engine validates input.
Why
The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.
How
An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may execute code or commands in the affected security context.
What
A remote code execution vulnerability exists in the way that the MSHTML engine improperly validates input. An attacker could execute arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker who successfully exploited the vulnerability could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. In a HTML editing attack scenario, an attacker could trick a user into editing a specially crafted file that is designed to exploit the vulnerability. The security update addresses the vulnerability by modifying how MSHTML engine validates input.
Why
The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.
How
An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may execute code or commands in the affected security context.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- a network path → vulnerable operation → execute code or commands in the affected security context
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- Required interaction required
- Attack complexity
- High: exploitation depends on specific conditions
- Security boundary
- Unchanged: impact remains within the vulnerable component's security authority
- Weakness
?
CWE means Common Weakness Enumeration. - CWE not yet assigned
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:CCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.- Post-exploitation / living off the land
- After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Patch available
- Action
- Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
- Workaround
- No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 21 May 2020 · Last source change 19 Aug 2026, 16:33 UTC · CWE not yet assigned
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2020-11956
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceUnavailable
NVD statusNVD modified after enrichment
Missing structured fields: CWE classification. Missing data is not evidence of low risk; review the primary advisory.
Material change intelligence
View recent updates ↗What changed after publication
- Vendor guidanceAuthoritative vendor guidance changed: added remediation: portal.msrc.microsoft.com/CVE-2020-1064; removed patch: msrc.microsoft.com/CVE-2020-1064; removed remediation: msrc.microsoft.com/CVE-2020-1064.portal.msrc.microsoft.com ↗
- Before
- patch: msrc.microsoft.com/CVE-2020-1064 · patch: portal.msrc.microsoft.com/CVE-2020-1064 · remediation: msrc.microsoft.com/CVE-2020-1064
- After
- patch: portal.msrc.microsoft.com/CVE-2020-1064 · remediation: portal.msrc.microsoft.com/CVE-2020-1064
- Vendor guidanceAuthoritative vendor guidance changed: added patch: msrc.microsoft.com/CVE-2020-1064; added remediation: msrc.microsoft.com/CVE-2020-1064; removed remediation: portal.msrc.microsoft.com/CVE-2020-1064.msrc.microsoft.com ↗
- Before
- patch: portal.msrc.microsoft.com/CVE-2020-1064 · remediation: portal.msrc.microsoft.com/CVE-2020-1064
- After
- patch: msrc.microsoft.com/CVE-2020-1064 · patch: portal.msrc.microsoft.com/CVE-2020-1064 · remediation: msrc.microsoft.com/CVE-2020-1064
- Affected versionsThe structured affected or fixed version information changed.CNA ↗
- Before
- Windows Server 2008 for 32-bit Systems Service Pack 2; Windows Server 2008 for x64-based Systems Service Pack 2; Windows 10 Version 1803 for 32-bit Systems; Windows 10 Version 1803 for x64-based Systems; Windows 10 Version 1803 for ARM64-based Systems; Windows 10 Version 1809 for 32-bit Systems; Windows 10 Version 1809 for x64-based Systems; Windows 10 Version 1809 for ARM64-based Systems · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
- After
- 1.0.0 < publication · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
- CVSS scoreCVSS vector changed while the displayed base score remained 7.5.CNA ↗
- Before
- 7.5 (CVSS 3.1 · NIST NVD · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H)
- After
- 7.5 (CVSS 3.1 · CNA · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C)
CVE published
Fixed release or patch reference recorded
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.