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CVE Record

CVE-2020-0878: Microsoft Browser Memory Corruption Vulnerability

<p>A remote code execution vulnerability exists in the way that Microsoft browsers access objects in memory. The vulnerability could corrupt memory in a way that could allow an attacker to execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. If the current user is logged on with administrative user rights, the attacker 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.</p> <p>An attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft browsers, and then convince a user to view the website. The attacker could also take advantage of compromised websites, or websites that accept or host user-provided content or advertisements, by adding specially crafted content that could exploit the vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically via an enticement in email or instant message, or by getting them to open an email attachment.</p> <p>The security update addresses the vulnerability by modifying how Microsoft browsers handle objects in memory.</p>

MediumCVSS 4.2Known exploitedUpdated
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This is a Microsoft browser memory corruption flaw that can let an attacker run code as the signed-in user after the user views attacker-controlled content. Business risk is higher where legacy Microsoft browsers remain in use, especially by administrators.

Executive priority

Treat this as a high-priority legacy browser remediation item because CISA lists it as known exploited, despite a medium CVSS score. Prioritize systems used by privileged users and environments where Internet Explorer or EdgeHTML remains operational.

Technical view

CVE-2020-0878 is a CWE-787 memory handling vulnerability in Microsoft browser object access. The bundled CVSS is 4.2: network reachable, no privileges, high attack complexity, and user interaction required. Successful exploitation can execute arbitrary code in the current user context.

Likely exposure

Exposure is most likely on systems still using Internet Explorer 9, Internet Explorer 11, EdgeHTML-based Microsoft Edge, or affected ChakraCore. Risk depends on users reaching malicious, compromised, ad-supported, or user-content websites through those technologies.

Exploitation context

CISA KEV inclusion supports known exploitation. The provided sources do not identify campaigns, exploit maturity, or affected deployment prevalence. Microsoft describes web or attachment-driven social engineering where attackers must convince users to view crafted content.

Researcher notes

Do not infer Chromium-based Edge exposure from this bundle; it names EdgeHTML-based Edge, IE 9, IE 11, and ChakraCore. Public evidence here confirms exploitation via KEV but does not provide campaign details, indicators, or exploit mechanics.

Mitigation direction

  • Apply Microsoft’s security update for CVE-2020-0878 where applicable.
  • Inventory and retire affected legacy Microsoft browsers where possible.
  • Restrict administrative users from routine web browsing.
  • Check current Microsoft guidance for product-specific remediation details.
  • Reduce exposure to untrusted web content on legacy systems.

Validation and detection

  • Confirm affected browser and ChakraCore versions across managed assets.
  • Verify Microsoft security updates are installed on exposed systems.
  • Review whether administrators use affected browsers for daily browsing.
  • Check endpoint telemetry for legacy browser execution after patching.
  • Confirm browser hardening policies apply to legacy Microsoft browsers.
Prepared
Confidence
high
Sources
4

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-787: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2020-0878 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
4.2 (3.1)
Known Exploited
Yes
Published

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N/E:P/RL:O/RC:C

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
3Source links

CISA KEV status

Status
Known exploited
Source
CISA / ADP
Date added
Not provided

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
4.2CVSS 3.1MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N/E:P/RL:O/RC:C1.62.5Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

4.2Medium
CVSS 3.1 vector shape for CVE-2020-0878Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N/E:P/RL:O/RC:C

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone
Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
MicrosoftChakraCore0Listed
MicrosoftMicrosoft Edge (EdgeHTML-based)1.0..0Listed
MicrosoftInternet Explorer 91.0.0Listed
MicrosoftInternet Explorer 111.0.0Listed
Weakness

CWE details

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-787 · source CWE mapping

Out-of-bounds Write

Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.