CVE-2023-3970Public exploitNetwork attack vector

Stored cross-site scripting via executable SVG upload

Published Jul 27, 2023 · Updated Aug 2, 2024

Stored cross-site scripting in GZ Scripts Availability Booking Calendar PHP 1.0 allows remote authenticated users to execute script via an SVG upload. The Image Handler accepts an img multipart upload containing active SVG script and serves the file without neutralizing its executable content. An authenticated account is required, and exploitation runs attacker-controlled JavaScript when another account holder opens the uploaded image in a browser.

CVSS severity5.4
Medium
EPSS probability0.56%
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 GZ Scripts Availability Booking Calendar PHP 1.0 allows remote authenticated users to execute script via an SVG upload. The Image Handler accepts an img multipart upload containing active SVG script and serves the file without neutralizing its executable content. An authenticated account is required, and exploitation runs attacker-controlled JavaScript when another account holder opens the uploaded image in a browser.

The record

CVE
CVE-2023-3970
Published
Jul 27, 2023
Updated
Aug 2, 2024
Vendor
GZ Scripts
Product
Availability Booking Calendar PHP
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 27, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 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=1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GZ Scripts · Availability Booking Calendar PHPversion=1.0

Published CVSS scores

5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
4.0VulDBAV:N/AC:L/Au:S/C:N/I:P/A:N
3.5VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
3.5VulDBCVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/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-79Cross 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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