CVE-2025-23041Network attack vector

Unauthenticated length-limit bypass via client-only validation

Published Jan 14, 2025 · Updated Jan 14, 2025

Improper input validation in Umbraco Forms allows remote attackers to submit answers beyond editor-configured length limits. The Short and Long Answer fields enforce editor-configured maximums in client-side controls, but the server accepts submissions without repeating the check. An unauthenticated network user needs access to a published form; an overlong answer bypasses its length constraint and reaches server-side processing.

CVSS severity5.8
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Umbraco Forms allows remote attackers to submit answers beyond editor-configured length limits. The Short and Long Answer fields enforce editor-configured maximums in client-side controls, but the server accepts submissions without repeating the check. An unauthenticated network user needs access to a published form; an overlong answer bypasses its length constraint and reaches server-side processing.

The record

CVE
CVE-2025-23041
Published
Jan 14, 2025
Updated
Jan 14, 2025
Vendor
Umbraco
Product
Umbraco Forms
Classifications
CWE-20, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Jan 14, 2025Record 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=>= 10.0.0, < 10.5.7
  2. Affected versionversion=>= 11.0.0, < 13.2.2
  3. Affected versionversion=>= 14.0.0, < 14.1.2
  4. Affected versionversion=< 8.13.16

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Umbraco · Umbraco Formsversion=>= 10.0.0, < 10.5.7; version=>= 11.0.0, < 13.2.2; version=>= 14.0.0, < 14.1.2; version=< 8.13.16

Published CVSS scores

5.8GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1190Exploit Public-Facing Application

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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