CVE-2020-27224Public exploitNetwork attack vector

Code execution via unsanitized Markdown preview

Published Feb 24, 2021 · Updated Aug 4, 2024

Cross-site scripting in Eclipse Theia 1.2.0 and earlier allows remote attackers to execute arbitrary code through Markdown Preview. The @theia/preview component renders attacker-controlled Markdown as HTML without sanitizing executable markup before displaying it. Execution requires a user to open the crafted Markdown preview and runs with the privileges available to the affected Theia application.

CVSS severity9.6
Critical
EPSS probability2.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Eclipse Theia 1.2.0 and earlier allows remote attackers to execute arbitrary code through Markdown Preview. The @theia/preview component renders attacker-controlled Markdown as HTML without sanitizing executable markup before displaying it. Execution requires a user to open the crafted Markdown preview and runs with the privileges available to the affected Theia application.

The record

CVE
CVE-2020-27224
Published
Feb 24, 2021
Updated
Aug 4, 2024
Vendor
The Eclipse Foundation
Product
Eclipse Theia
Classifications
CWE-79, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=1.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Eclipse Foundation · Eclipse Theiaversion=unspecified <=1.2.0

Published CVSS scores

9.6GitHub Security Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.002Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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