CVE-2021-24332Public exploitNetwork attack vector

Stored XSS via unescaped optimization settings

Published May 24, 2021 · Updated Aug 3, 2024

Stored XSS in Optimizing Matters Autoptimize before 2.8.4 allows remote authenticated users to execute scripts via plugin settings. The settings handlers persist crafted autoptimize_css_defer_inline and autoptimize_ccss_key values, then render them into the Inline and Defer CSS and Critical CSS API Key fields without adequate sanitization or output escaping. High-privilege settings access is required, and execution occurs when a user loads an affected settings page.

CVSS severity4.8
Medium
EPSS probability0.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Optimizing Matters Autoptimize before 2.8.4 allows remote authenticated users to execute scripts via plugin settings. The settings handlers persist crafted autoptimize_css_defer_inline and autoptimize_ccss_key values, then render them into the Inline and Defer CSS and Critical CSS API Key fields without adequate sanitization or output escaping. High-privilege settings access is required, and execution occurs when a user loads an affected settings page.

The record

CVE
CVE-2021-24332
Published
May 24, 2021
Updated
Aug 3, 2024
Vendor
Optimizing Matters
Product
Autoptimize
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. May 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.8.4 <2.8.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Optimizing Matters · Autoptimizeversion=2.8.4 <2.8.4

Published CVSS scores

3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
4.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
5.5Wordfence IntelligenceCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript/JScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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