Cyber Resilience

CVE-2021-39356

MediumPublic PoC

Published: 21 October 2021

Published
21 October 2021
Modified
21 November 2024
KEV Added
—
Patch
—
CVSS Score v3.1 5.5 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
EPSS Score 0.0083 75.0th percentile
Risk Priority 11 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-39356 is a medium-severity Cross-site Scripting (CWE-79) vulnerability in Content Staging Project Content Staging. Its CVSS base score is 5.5 (Medium).

Operationally, ranked in the top 25.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

The Content Staging WordPress plugin is vulnerable to Stored Cross-Site Scripting due to insufficient input validation and escaping via several parameters that are echo'd out via the ~/templates/settings.php file which allowed attackers with administrative user access to inject arbitrary web…

more

scripts, in versions up to and including 2.0.1. This affects multi-site installations where unfiltered_html is disabled for administrators, and sites where unfiltered_html is disabled.

CWE(s)
CWE-79

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

content staging project
content staging
≤ 2.0.1

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing
addresses: CWE-79

Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.

SI-10 Information Input Validation
addresses: CWE-79

Validates web inputs to reject script-related content that could produce XSS.

SI-15 Information Output Filtering
addresses: CWE-79

Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.

References