CVE-2021-47950Public exploitNetwork attack vector

Stored XSS via unneutralized smilie description

Published May 10, 2026 · Updated May 10, 2026

Stored cross-site scripting in Advanced Guestbook 2.4.4 allows remote authenticated users to execute JavaScript through s_emotion. The smilies editor stores the POSTed description without neutralizing script markup and renders the value in admin.php. Administrative access is required to plant the payload, and execution occurs when an administrator revisits the Smilies tab.

CVSS severity5.1
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in Advanced Guestbook 2.4.4 allows remote authenticated users to execute JavaScript through s_emotion. The smilies editor stores the POSTed description without neutralizing script markup and renders the value in admin.php. Administrative access is required to plant the payload, and execution occurs when an administrator revisits the Smilies tab.

The record

CVE
CVE-2021-47950
Published
May 10, 2026
Updated
May 10, 2026
Vendor
Chi Kien Uong
Product
Advanced Guestbook
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 10, 2026CVE publishedPublication date reported by the CVE source.
  2. May 10, 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=2.4.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Chi Kien Uong · Advanced Guestbookversion=2.4.4

Published CVSS scores

5.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
6.4VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
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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