External risk intelligence

Hyland Alfresco Argument Injection Remote Code Execution

CVE advisorySeverity: CRITICAL (CVSS 9.3)

CVE-2026-26339

The Hyland Alfresco Transformation Service is a component of a document management system. While these systems often reside within internal enterprise networks to process sensitive content, they may be exposed to the internet in some deployments to support external document submission or transformation workflows. However, it is not inherently designed as an edge gateway or public-facing service.

Server-Side Request Forgery

Hyland Alfresco Transform Service

before 4.2.3before 5.2.4

Halo Surface Signal: 3 out of 5 — possibly public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability has been identified in Hyland's Alfresco Transformation Service, which handles document processing. This issue could allow an unauthenticated attacker to execute arbitrary code remotely, potentially impacting the confidentiality, integrity, and availability of the system. The primary concern is to confirm if this specific service is in use and if it is exposed in a way that could be targeted.

Unauthenticated remote code execution risk.
Affects document processing functionality.
Confirm relevance and exposure.

Attack Path

How an attacker could exploit the issue

An unauthenticated attacker could reach the Hyland Alfresco Transformation Service from the network and submit specially crafted documents. This would trigger an argument injection vulnerability within the document processing functionality, potentially leading to remote code execution.

No authentication required.
Malicious document processing.
Remote code execution.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow unauthenticated attackers to execute arbitrary code on the affected system when processing documents. This could impact the integrity and availability of the document processing functionality.

System data could be compromised.
Remote code execution is possible.
Service integrity and availability may be affected.

Operational Fix

Recommended remediation, mitigation, and detection steps

The Hyland Alfresco Transformation Service, used for document processing, is susceptible to remote code execution. Ownership of this vulnerability will likely fall to the teams managing the Alfresco platform or the application owners responsible for the business processes it supports. The immediate priority is to identify all instances of the affected service, determine their exposure and criticality, and then plan remediation based on these findings.

Identify Alfresco platform owners.
Verify service exposure and criticality.
Plan risk-based remediation.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the Hyland Alfresco Transformation Service?

This software is a component within Hyland's Alfresco document management platform. It is specifically responsible for handling document processing tasks, such as converting files between different formats. Organizations use this service to automate content workflows, ensuring that documents uploaded to the system are readable and functional across various business applications.

How does CVE-2026-26339 work?

This vulnerability is classified as an argument injection issue. It occurs when the software's document processing component fails to properly filter input. An attacker can send a specially crafted document that introduces malicious commands into the system's processing arguments. Because of this weakness, the system inadvertently executes those injected instructions, resulting in unauthorized remote code execution.

Do I need to be authenticated to trigger this flaw?

No, authentication is not required to trigger this vulnerability. The flaw exists within the document processing functionality itself, allowing an unauthenticated attacker to interact with the service directly. Please note that the vulnerability is triggered through the specific submission of malicious files for processing; it does not occur simply by having the service active on a network without receiving such input.

Is my system at risk based on Halo Surface Signal?

Halo Surface Signal indicates that while this service is often kept on internal networks, it can be internet-facing in certain deployments, such as those supporting external document uploads. If your instance is accessible from the internet, it faces a higher level of risk because it is reachable by external actors. You should prioritize assessing whether your deployment allows external traffic to reach this specific service.

What are the first steps to address this CVE?

Start by identifying all instances of the Alfresco Transformation Service within your environment to determine which systems are running affected versions. Once located, verify the network exposure of these instances to understand their accessibility. Finally, engage with the teams responsible for your Alfresco platform to coordinate a transition to the updated software versions provided by Hyland, ensuring the vulnerability is remediated.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.