CVE-2020-4046Public exploitNetwork attack vector

Stored XSS via unsafe iframe title removal

Published Jun 12, 2020 · Updated Aug 4, 2024

Stored XSS in affected WordPress block editor releases allows remote authenticated users to execute JavaScript through crafted embed posts. wp_filter_oembed_iframe_title_attribute ran after oEmbed sanitization and globally removed a crafted iframe title string, exposing an onload attribute that the earlier filter had neutralized. Contributor-level post access, outbound retrieval of attacker-controlled oEmbed data, and a higher-privileged user viewing the post are required; the script runs in that user's wp-admin context.

CVSS severity5.4
Medium
EPSS probability2.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in affected WordPress block editor releases allows remote authenticated users to execute JavaScript through crafted embed posts. wp_filter_oembed_iframe_title_attribute ran after oEmbed sanitization and globally removed a crafted iframe title string, exposing an onload attribute that the earlier filter had neutralized. Contributor-level post access, outbound retrieval of attacker-controlled oEmbed data, and a higher-privileged user viewing the post are required; the script runs in that user's wp-admin context.

The record

CVE
CVE-2020-4046
Published
Jun 12, 2020
Updated
Aug 4, 2024
Vendor
WordPress.org
Product
WordPress
Classifications
CWE-79, CWE-80, T1059.007, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 12, 2020CVE 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

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=>= 3.7.0, < 3.7.34
  2. Affected versionversion=>= 3.8.0, < 3.8.34
  3. Affected versionversion=>= 3.9.0, < 3.9.32
  4. Affected versionversion=>= 4.0.0, < 4.0.31
  5. Affected versionversion=>= 4.1.0, < 4.1.31
  6. Affected versionversion=>= 4.2.0, < 4.2.28
  7. Affected versionversion=>= 4.3.0, < 4.3.24
  8. Affected versionversion=>= 4.4.0, < 4.4.23
  9. Affected versionversion=>= 4.5.0, < 4.5.22
  10. Affected versionversion=>= 4.6.0, < 4.6.19
  11. Affected versionversion=>= 4.7.0, < 4.7.18
  12. Affected versionversion=>= 4.8.0, < 4.8.14
  13. Affected versionversion=>= 4.9.0, < 4.9.15
  14. Affected versionversion=>= 5.0.0, < 5.0.10
  15. Affected versionversion=>= 5.1.0, < 5.1.6
  16. Affected versionversion=>= 5.2.0, < 5.2.7
  17. Affected versionversion=>= 5.3.0, < 5.3.4
  18. Affected versionversion=>= 5.4.0, < 5.4.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

WordPress.org · WordPressversion=>= 3.7.0, < 3.7.34; version=>= 3.8.0, < 3.8.34; version=>= 3.9.0, < 3.9.32; version=>= 4.0.0, < 4.0.31; version=>= 4.1.0, < 4.1.31; version=>= 4.2.0, < 4.2.28; version=>= 4.3.0, < 4.3.24; version=>= 4.4.0, < 4.4.23; version=>= 4.5.0, < 4.5.22; version=>= 4.6.0, < 4.6.19; version=>= 4.7.0, < 4.7.18; version=>= 4.8.0, < 4.8.14; version=>= 4.9.0, < 4.9.15; version=>= 5.0.0, < 5.0.10; version=>= 5.1.0, < 5.1.6; version=>= 5.2.0, < 5.2.7; version=>= 5.3.0, < 5.3.4; version=>= 5.4.0, < 5.4.2

Published CVSS scores

5.4NISTCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.4GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.5NISTAV:N/AC:M/Au:S/C:N/I:P/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
T1059.007Command and Scripting Interpreter: JavaScript/JScript
T1203Exploitation for Client Execution

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

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