CVE-2023-4187Public exploitNetwork attack vector

Stored script execution via unfiltered string fields

Published Aug 5, 2023 · Updated Oct 9, 2024

Stored XSS in InstantCMS before 2.16.1-git allows remote authenticated users to execute script in another user's browser. The string-field storage path returns HTML-enabled values without passing them through the html_filter hook, so submitted markup is persisted and later rendered. Exploitation requires high-privilege access and a victim to view the stored value, enabling browser-context data access or content modification.

CVSS severity3.5
Low
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Stored XSS in InstantCMS before 2.16.1-git allows remote authenticated users to execute script in another user's browser. The string-field storage path returns HTML-enabled values without passing them through the html_filter hook, so submitted markup is persisted and later rendered. Exploitation requires high-privilege access and a victim to view the stored value, enabling browser-context data access or content modification.

The record

CVE
CVE-2023-4187
Published
Aug 5, 2023
Updated
Oct 9, 2024
Vendor
InstantCMS Team
Product
InstantCMS
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Aug 5, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 9, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2.16.1-git

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

InstantCMS Team · InstantCMSversion=0 <2.16.1-git
InstantCMS Team · InstantCMS 2version=unspecified <2.16.1-git

Published CVSS scores

4.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
3.5huntr.devCVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:U/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
Privilegesadmin
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo