CVE-2026-5217Public exploitNetwork attack vector

Unauthenticated stored XSS via unescaped srcset descriptor

Published Apr 11, 2026 · Updated Apr 11, 2026

Stored XSS in Themeisle Optimole 4.2.2 and earlier allows remote attackers to execute scripts through a crafted srcset descriptor. rest.php applies sanitize_text_field() to the s parameter without neutralizing double quotes, and tag_replacer.php later inserts the cached descriptor verbatim into an HTML srcset attribute. Publicly exposed HMAC and timestamp values allow unauthenticated REST requests; loading a page containing a poisoned image executes the stored script.

CVSS severity7.2
High
EPSS probability0.44%
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 Themeisle Optimole 4.2.2 and earlier allows remote attackers to execute scripts through a crafted srcset descriptor. rest.php applies sanitize_text_field() to the s parameter without neutralizing double quotes, and tag_replacer.php later inserts the cached descriptor verbatim into an HTML srcset attribute. Publicly exposed HMAC and timestamp values allow unauthenticated REST requests; loading a page containing a poisoned image executes the stored script.

The record

CVE
CVE-2026-5217
Published
Apr 11, 2026
Updated
Apr 11, 2026
Vendor
Query Solutions Ltd.
Product
Optimole
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 11, 2026Record 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=0 <=4.2.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Query Solutions Ltd. · Optimoleversion=0 <=4.2.2

Published CVSS scores

7.2WordfenceCVSS:3.1/AV:N/AC:L/PR:N/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.

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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
Privilegesunauthenticated
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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