CVE-2023-5621Network attack vector

Administrator-level stored XSS via unescaped image titles

Published Oct 18, 2023 · Updated Apr 8, 2026

Stored XSS in Thumbnail Slider With Lightbox 1.0 and earlier allows remote authenticated users to inject scripts through image titles. The plugin stores the Image Title field without sufficient sanitization and renders it without escaping, causing saved markup to execute when a page displays the slider. Administrator-level access is required, and exposure is limited to multisite installations or sites where unfiltered_html is disabled; executed scripts run in a visitor's browser and can act within that visitor's session.

CVSS severity4.4
Medium
EPSS probability0.40%
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 Thumbnail Slider With Lightbox 1.0 and earlier allows remote authenticated users to inject scripts through image titles. The plugin stores the Image Title field without sufficient sanitization and renders it without escaping, causing saved markup to execute when a page displays the slider. Administrator-level access is required, and exposure is limited to multisite installations or sites where unfiltered_html is disabled; executed scripts run in a visitor's browser and can act within that visitor's session.

The record

CVE
CVE-2023-5621
Published
Oct 18, 2023
Updated
Apr 8, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Oct 18, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
4.4WordfenceCVSS:3.1/AV:N/AC:H/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 exploitUnconfirmed

Weakness, pattern, technique

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

Public exploit references

No public exploit references are available in this record.

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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