CVE-2021-29484Public exploitNetwork attack vector

Admin takeover via unvalidated cross-origin messages

Published Apr 29, 2021 · Updated Aug 3, 2024

DOM-based XSS in Ghost 4.0.0 through 4.3.2 allows remote attackers to take over Ghost Admin accounts through a malicious webpage. The /ghost/preview page passes cross-origin message data to document.write without validating the sender's origin and permits framing. A logged-in staff user must visit attacker-controlled content, after which injected JavaScript can perform any permitted administrative action.

CVSS severity7.6
High
EPSS probability7.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

DOM-based XSS in Ghost 4.0.0 through 4.3.2 allows remote attackers to take over Ghost Admin accounts through a malicious webpage. The /ghost/preview page passes cross-origin message data to document.write without validating the sender's origin and permits framing. A logged-in staff user must visit attacker-controlled content, after which injected JavaScript can perform any permitted administrative action.

The record

CVE
CVE-2021-29484
Published
Apr 29, 2021
Updated
Aug 3, 2024
Vendor
Ghost Foundation
Product
Ghost
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 29, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=>= 4.0.0, < 4.3.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Ghost Foundation · Ghostversion=>= 4.0.0, < 4.3.3

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
7.6GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:H/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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')
T1189Drive-by Compromise

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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