Cyber Resilience

CVE-2020-1020

Memory Safety in Microsoft Windows 10 1803

CISA KEVActive ExploitationEUVD ExploitedMemory Safety
Published
15 April 2020
Modified
29 October 2025
KEV Added
03 November 2021
Patch / advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.65 99.2th percentile
Risk Priority 90 floored blend · peak EPSS

Summary

CVE-2020-1020 is a high-severity Out-of-bounds Write (CWE-787) vulnerability in Microsoft Windows 10 1803. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 0.8% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

A remote code execution vulnerability tracked as CVE-2020-1020 exists in the Windows Adobe Type Manager Library when it improperly processes a specially crafted multi-master font in Adobe Type 1 PostScript format. The flaw affects Microsoft Windows systems and is distinct from the related CVE-2020-0938. It carries a CVSS 3.1 base score of 8.8 and is associated with CWE-787.

An unauthenticated attacker can exploit the issue over a network by convincing a user to open or preview a malicious document containing the crafted font. Successful exploitation grants remote code execution with high impact to confidentiality, integrity, and availability on all affected Windows versions except Windows 10, where the impact is limited.

Microsoft security advisories at portal.msrc.microsoft.com detail patches and mitigation guidance for the vulnerability. The flaw is also catalogued by CISA among actively exploited vulnerabilities in the wild.

EU & UK References

Vulnerability Data

A remote code execution vulnerability exists in Microsoft Windows when the Windows Adobe Type Manager Library improperly handles a specially-crafted multi-master font - Adobe Type 1 PostScript format.For all systems except Windows 10, an attacker who successfully exploited the vulnerability…

more

could execute code remotely, aka 'Adobe Font Manager Library Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2020-0938.

CWE(s)
KEV Date Added
03 November 2021

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2020-1027Same product: Microsoft Windows 10 1507both on KEV
CVE-2020-0938Same product: Microsoft Windows 10 1507both on KEV
CVE-2020-1054Same product: Microsoft Windows 10 1507both on KEV
CVE-2020-0968Same product: Microsoft Windows 10 1507both on KEV
CVE-2020-1380Same product: Microsoft Windows 10 1507both on KEV
CVE-2020-0986Same product: Microsoft Windows 10 1507both on KEV
CVE-2020-0878Same product: Microsoft Windows 10 1507both on KEV
CVE-2018-8653Same product: Microsoft Windows 10 1507both on KEV
CVE-2019-1367Same product: Microsoft Windows 10 1607both on KEV
CVE-2021-33742Same product: Microsoft Windows 10 1507both on KEV

Affected Assets

microsoft
windows 10 1507
all versions
microsoft
windows 10 1607
all versions
microsoft
windows 10 1709
all versions
microsoft
windows 10 1803
all versions
microsoft
windows 10 1809
all versions
microsoft
windows 10 1903
all versions
microsoft
windows 10 1909
all versions
microsoft
windows 7
all versions
microsoft
windows 8.1
all versions
microsoft
windows rt 8.1
all versions
+6 more product configuration(s) — see NVD for full list

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-787

Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.

PR.PS-02 partial match
prevents

Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development and acceptance can detect and prevent out-of-bounds write defects.

prevents

Secure development life cycle mandates practices that prevent out-of-bounds writes.

prevents

Application security requirements can specify bounds-checking and safe memory handling.

prevents

Secure architecture and engineering principles reduce the likelihood of buffer overflows.

prevents

Secure coding directly addresses out-of-bounds writes through language choice and coding standards.

prevents

Change management can enforce review gates that catch unsafe memory operations before deployment.

References