CVE-2023-4879Network attack vector

Stored script execution via unfiltered HTML fields

Published Sep 10, 2023 · Updated Sep 26, 2024

Stored cross-site scripting in InstantCMS 2 before 2.16.1.-git allows remote authenticated users to execute scripts in an administrator's browser. HTML description fields for content types, datasets, and filters stored submitted markup without passing it through the html_filter hook. Administrative access is required to store a payload, and execution requires another user to view affected content, exposing that user's browser session context.

CVSS severity4.8
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 cross-site scripting in InstantCMS 2 before 2.16.1.-git allows remote authenticated users to execute scripts in an administrator's browser. HTML description fields for content types, datasets, and filters stored submitted markup without passing it through the html_filter hook. Administrative access is required to store a payload, and execution requires another user to view affected content, exposing that user's browser session context.

The record

CVE
CVE-2023-4879
Published
Sep 10, 2023
Updated
Sep 26, 2024
Vendor
InstantCMS Team
Product
InstantCMS 2
Classifications
CWE-79, T1203
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Sep 10, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 26, 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=unspecified <2.16.1.-git

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

InstantCMS Team · InstantCMS 2version=unspecified <2.16.1.-git

Published CVSS scores

3.5huntr.devCVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:N/A:L
4.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/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 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')
T1203Exploitation for Client Execution

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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