CVE-2021-24964: LiteSpeed Cache < 4.4.4 - IP Check Bypass to Unauthenticated Stored XSS

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2022-01-03 · updated 2026-06-17
Weakness: CWE-79

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.

Affected products

LiteSpeed Technologies LiteSpeed Cache: before 4.4.4 — fixed in 4.4.4

How to fix

Upgrade to a fixed version: LiteSpeed Technologies LiteSpeed Cache 4.4.4. Check the vendor advisory for mitigations.

References

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