LiteSpeed Cache Plugin HTML Optimization Enables XSS Injection

The LiteSpeed Cache WordPress plugin before 7.9.2 does not limit one of its HTML optimization routines to stylesheet content, so it can delete the markup that closes an attribute in the rendered page, and combined with unescaped comment author output this allows unauthenticated users whose comments are published to inject event-handler attributes that run JavaScript in the browser of any visitor, including a logged-in administrator, viewing front-end pages while the optimization is enabled.

Casky was already ahead

This CVE exploits attack patterns that Casky's 323matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

The LiteSpeed Cache WordPress plugin before version 7.9.2 contains a stored cross-site scripting (XSS) vulnerability that exploits a flaw in its HTML optimization routine. The plugin's optimizer incorrectly processes non-stylesheet content, deleting markup that closes HTML attributes in rendered pages. When combined with unescaped comment author output, this allows unauthenticated attackers to inject malicious event-handler attributes (like onclick, onload, or onmouseover) into comments. Once a comment is published, any visitor—including administrators—who views the front-end page executes the attacker's JavaScript in their browser. This vulnerability affects all WordPress sites running the vulnerable plugin version with optimization enabled, making it a critical threat to site integrity, admin account compromise, and visitor data theft.

Casky's 323 matched skills leverage Claude's extended reasoning to detect this attack pattern across MITRE ATT&CK's Initial Access (TA0001) and Reconnaissance (TA0043) techniques. Practitioners using Casky would identify detection signals including: malformed HTML attribute markup in cached page output, unusual event-handler attributes in comment fields, rendering inconsistencies between optimized and non-optimized pages, and JavaScript execution anomalies on front-end visitors. The platform maps these indicators to CWE-79 (Improper Neutralization of Input During Web Page Generation) and surfaces attack chains showing how unauthenticated comment submission leads to persistent payload execution. Security teams gain visibility into both the root cause (broken HTML optimization logic) and exploitation indicators (injected event handlers), enabling rapid response before administrative sessions are compromised.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

323 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-113500.

Abuse of Public-Facing API: Mobile API Abuse

mobile security · low

Run

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

MITRE ATT&CK Techniques

TA0001 TA0043

Investigate the attack patterns behind CVE-2026-113500

Casky has 323 skills that investigate the attack patterns behind CVE-2026-113500. Run one and get CVSS-scored findings in 3 minutes.

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