Is CVE-2021-39320 in the CISA KEV catalog?

No. CVE-2021-39320 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-39320?

CVE-2021-39320 has a CVSS v3 base score of 6.1 (MEDIUM).

What is the EPSS score for CVE-2021-39320?

CVE-2021-39320 has an EPSS score of 2.33% (82th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-39320?

Upgrade underconstruction to 1.19 or later.

CVE & CISA-KEV Catalog

CVE-2021-39320

MEDIUMEPSS 82th pctl

6.1

CVSS v3

NVD

Description

The underConstruction plugin <= 1.18 for WordPress echoes out the raw value of `$GLOBALS['PHP_SELF']` in the ucOptions.php file. On certain configurations including Apache+modPHP, this makes it possible to use it to perform a reflected Cross-Site Scripting attack by injecting malicious code in the request path.

CWE-79Cross-Site Scripting (XSS)

How to fix

Remediation Available

underconstructionNVD

Affected:< 1.19Fixed in:1.19CVE-2021-39320derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeChanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Exploit Intelligence

2.33%probability of exploitation in 30 days

82ndpercentile

Elevated risk: more likely to be exploited than 82% of all known CVEs.

References

Third-Party Advisory2

Related Vulnerabilities

Other CWE-79 (Cross-Site Scripting (XSS)) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2020-11022	Medium	6.9	99%	-	Fix
CVE-2019-3929	Critical	9.8	99%	KEV	Fix
CVE-2020-9496	Medium	6.1	99%	-	-
CVE-2023-28341	Medium	6.1	99%	-	Fix
CVE-2018-12998	Medium	6.1	98%	-	-
CVE-2025-4123	High	7.6	98%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.