CVE-2021-39356Public exploitNetwork attack vector

Stored script execution via unescaped settings parameters

Published Oct 21, 2021 · Updated Feb 14, 2025

Stored XSS in Content Staging 2.0.1 and earlier allows remote authenticated users to inject scripts through plugin settings. The templates/settings.php view echoes several attacker-controlled parameters without sufficient validation or output escaping. Exploitation requires administrative access and a site where unfiltered_html is disabled; the stored script executes when an affected page is rendered.

CVSS severity5.5
Medium
EPSS probability0.99%
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 Content Staging 2.0.1 and earlier allows remote authenticated users to inject scripts through plugin settings. The templates/settings.php view echoes several attacker-controlled parameters without sufficient validation or output escaping. Exploitation requires administrative access and a site where unfiltered_html is disabled; the stored script executes when an affected page is rendered.

The record

CVE
CVE-2021-39356
Published
Oct 21, 2021
Updated
Feb 14, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Oct 21, 2021CVE publishedPublication date reported by the CVE source.
  2. Feb 14, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
4.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
5.5WordfenceCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

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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