CVE-2026-24687

Home/CVE/Umbraco Forms is a form builder that integrates with the Umbraco content management system. It's possible for an authent

CVE

Umbraco Forms is a form builder that integrates with the Umbraco content management system. It's possible for an authent

Umbraco Forms is a form builder that integrates with the Umbraco content management system. It's possible for an authenticated backoffice-user to enumerate and traverse paths/files on the systems filesystem and read their contents, on Mac/Linux Umbraco installations using Forms. As Umbraco Cloud runs in a Windows environment, Cloud users aren't affected.

This issue affects versions 16 and 17 of Umbraco Forms and is patched in 16.4.1 and 17.1.1. If upgrading is not immediately possible, users can mitigate this vulnerability by configuring a WAF or reverse proxy to block requests containing path traversal sequences (../, ..\) in the fileName parameter of the export endpoint, restricting network access to the Umbraco backoffice to trusted IP ranges, and/or blocking the /umbraco/forms/api/v1/export endpoint entirely if the export feature is not required. However, upgrading to the patched version is strongly recommended.

MEDIUM · CVSS 6.5 EPSS 0.00025

Monitor

No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence

Sigma rules8 YARA rules0

Look this up elsewhere - one-click external pivots

NVD CVE.org CISA Vulners Exploit-DB GitHub PoC VulnCheck KEV GreyNoise

▸ How to read a CVE - triage first, then detect and patch

This page is every public fact about CVE-2026-24687, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.

Triage: should I act now? Four signals, and they are not interchangeable:

CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked. EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal. CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score. Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.

How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.

Then what - two workflows:

Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits. PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.

Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).

View attack path from CVE-2026-24687

◆

ATT&CK techniques

Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.

T1078 · Valid Accounts

▤ Build a SIEM detection for these techniques

▤

CAPEC attack patterns

Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.

CAPEC-CAPEC-126 · Path Traversal CAPEC-CAPEC-64 · Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-CAPEC-76 · Manipulating Web Input to File System Calls CAPEC-CAPEC-78 · Using Escaped Slashes in Alternate Encoding CAPEC-CAPEC-79 · Using Slashes in Alternate Encoding

⬡

Weakness Classification

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

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Affected Products & Versions

umbraco forms>= 16.0.0 and < 16.4.1

umbraco forms>= 17.0.0 and < 17.1.1

▤

Affected Packages

Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.

NuGet Umbraco.Forms MODERATE fixed in 16.4.1

◈

Sigma Hunt Rules

Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.

producthighSuspicious Microsoft Office Child Process - MacOS

producthighRemote Access Tool - Renamed MeshAgent Execution - MacOS

producthighBinary Padding - MacOS

productmediumSuspicious Execution via macOS Script Editor

productmediumSystem Information Discovery Via Sysctl - MacOS

productmediumNew File Exclusion Added To Time Machine Via Tmutil - MacOS

Show all 8 top matches

productmediumSuspicious MacOS Firmware Activity

productmediumDisk Image Mounting Via Hdiutil - MacOS

▣

Scoring & Timeline

6.5

MEDIUM · CVSS v3.1 · [email protected]

View on NVD

Attack Vector

Network Adjacent Local Physical

Attack Complexity

Low High

Privileges Required

None Low High

User Interaction

None Required

Scope

Unchanged Changed

Confidentiality

None Low High

Integrity

None Low High

Availability

None Low High

Published to NVD29 Jan 2026 · 08:16 PM

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

SSVC triage · cisa-vulnrichment

Exploitation

none

Automatable

Technical impact

partial

SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.

🔗

References & Sources

Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.

https://github.com/umbraco/Umbraco.Forms.Issues/security/advisories/GHSA-hm5p-82g6-m3xhMitigationVendor Advisory