CVE-2021-24439Public exploitNetwork attack vector

Stored XSS via unescaped shortcode image class

Published Jul 12, 2021 · Updated Aug 3, 2024

Stored XSS in Kevin Leary Browser Screenshots before 1.7.6 allows remote authenticated users to execute script in visitors' browsers. The browser-shot shortcode inserts its image_class parameter into rendered markup without escaping, so a crafted attribute stores an event-handler payload. Contributor-level access is sufficient to plant the payload, and execution requires another user to view or preview the affected page.

CVSS severity5.4
Medium
EPSS probability0.62%
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 Kevin Leary Browser Screenshots before 1.7.6 allows remote authenticated users to execute script in visitors' browsers. The browser-shot shortcode inserts its image_class parameter into rendered markup without escaping, so a crafted attribute stores an event-handler payload. Contributor-level access is sufficient to plant the payload, and execution requires another user to view or preview the affected page.

The record

CVE
CVE-2021-24439
Published
Jul 12, 2021
Updated
Aug 3, 2024
Vendor
Kevin Leary
Product
Browser Screenshots
Classifications
CWE-79, CAPEC-592, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 12, 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=1.7.6 <1.7.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Kevin Leary · Browser Screenshotsversion=1.7.6 <1.7.6

Published CVSS scores

5.4WordfenceCVSS:3.1/AV:N/AC:L/PR:L/UI:R/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-592Stored XSS
T1059.007JavaScript/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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