Threats / Microsoft / CVE-2020-0938
CVE-2020-0938
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-09-19
Microsoft Windows vulnerability
Microsoft Windows Adobe Font Manager Library remote code execution vulnerability triggered by specially crafted multi-master fonts, allowing code execution with limited privileges on Windows 10 and full execution on other Windows versions.
Verdict
Today item — known-exploited.
An attacker can exploit this vulnerability by delivering a malicious multi-master font file to execute arbitrary code. On Windows 10, execution occurs within an AppContainer sandbox with restricted capabilities. On other Windows versions, the vulnerability permits unrestricted code execution.
CISA KEV Yes · 2021-11-034EPSS 0.69166 (verify live)5CVSS 7.8 (CISA)3CISA SSVC Exploitation: active · Automatable: no · Impact: total3
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
4 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03).
Probability (EPSS)
EPSS 0.69166 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 7.8 (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) · Affected: Microsoft, Windows. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
Weakness (CWE)
Mapped to CWE-787 Out-of-bounds Write — weakness family: Memory safety.CWE assignment from the public NVD record (may be stale); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: no · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 567 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious Adobe Type 1 PostScript multi-master font file designed to trigger memory corruption in the font manager library.
Business
The organization faces potential data breach, system compromise, or lateral movement depending on the Windows version deployed across the environment.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I deliver the font file through email, web download, or document embedding to target users.
Business
User systems become compromised upon opening or processing the malicious font, potentially affecting productivity and requiring incident response.
3
Lateral reach — past segmentation narrative 3
Attacker
On Windows 10, my code executes within an AppContainer sandbox with limited privileges; on other versions, I gain full system-level code execution.
Business
Depending on Windows version, the organization experiences either contained damage or full system compromise with risk of persistent access and data exfiltration.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05
Coverage & confidence
— what we know, and what we don’tEstablished (cited)
Coverage gaps — stated, not hidden
Disclosure & credit2
Catalogued by microsoftCNA
Credited with finding itLiubenjin and Zhiyi Zhang from Codesafe Team of Legendsec at Qi'anxin GroupfinderGoogle: Project Zero and Threat Analysis Groupfinder
Found an error? Propose a correction.
A correction is a cited counter-claim — it must cite a source,
gets reviewed by a second human, and is never auto-applied. See the
correction convention and our identity
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