Is CVE-2021-24964 in the CISA KEV catalog?

No. CVE-2021-24964 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-24964?

CVE-2021-24964 has a CVSS v3 base score of 6.1 (MEDIUM).

What is the EPSS score for CVE-2021-24964?

CVE-2021-24964 has an EPSS score of 1.22% (65th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-24964?

Upgrade litespeed cache to 4.4.4 or later.

CVE & CISA-KEV Catalog

CVE-2021-24964

MEDIUM

6.1

CVSS v3

NVD

Description

The LiteSpeed Cache WordPress plugin before 4.4.4 does not properly verify that requests are coming from QUIC.cloud servers, allowing attackers to make requests to certain endpoints by using a specific X-Forwarded-For header value. In addition, one of the endpoint could be used to set CSS code if a setting is enabled, which will then be output in some pages without being sanitised and escaped. Combining those two issues, an unauthenticated attacker could put Cross-Site Scripting payloads in pages visited by users.

CWE-79Cross-Site Scripting (XSS)

How to fix

Remediation Available

litespeed cacheNVD

Affected:< 4.4.4Fixed in:4.4.4CVE-2021-24964derived 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

1.22%probability of exploitation in 30 days

65thpercentile

Moderate risk: more likely to be exploited than 65% of all known CVEs.

References

Exploit1

wpscan.com

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 2025-05-22.