External risk intelligence

Mahara Text Block Vulnerability Allows Content Recall

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-42164

Mahara is a web-based ePortfolio system typically deployed as a public-facing web application for students and staff to access over the internet. Because the vulnerability exists within a core component of the web interface, it is commonly reachable in standard deployments.

Information Disclosure

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A critical vulnerability has been identified in Mahara, an ePortfolio system, impacting its text editing functionality. This issue could allow unauthorized access to and modification of user content. The primary concern is to confirm if your organization utilizes this specific technology and assess any potential exposure.

Text editing flaw affects ePortfolio software.
Confirm Mahara use to understand relevance.
Assess exposure if Mahara is deployed.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by crafting a malicious call that targets the Text block functionality within Mahara. This crafted call would enable the attacker to recall previously backed-up content from another Text section, potentially leading to unauthorized access and manipulation of sensitive information. The vulnerability resides in the way Mahara handles content retrieval within its Text blocks.

Exposed to the network.
Malicious call to Text block.
Information disclosure and modification.

Live Threat

Current exploitation, exposure, and threat context

When configured for external access, this vulnerability could allow an unauthenticated attacker to retrieve backed-up content from other text sections by crafting a specific call. This could expose previously saved or edited information within the application.

Text section content.
Crafted network calls.
Exposure of sensitive information.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in Mahara's Text block functionality requires immediate attention from the platform or application owners responsible for Mahara instances. The first practical step is to confirm the presence and reachability of Mahara, identify its business criticality, and then determine the accountable team for remediation. Planning the fix should be based on the assessed risk and potential impact.

Platform or application owners should take ownership.
Verify Mahara's presence and reachability.
Plan remediation based on risk assessment.

Supplementary metadata

CVSS vector

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Frequently asked questions

What is Mahara and how is it used?

Mahara is an open-source ePortfolio platform designed to help students, staff, and professionals document their learning journeys, manage personal development plans, and showcase their work. It provides web-based tools for users to create and share digital portfolios, acting as a collaborative social networking site often integrated into educational institutions.

What does CWE-200 mean for CVE-2026-42164?

CWE-200, or Exposure of Sensitive Information to an Unauthorized Actor, refers to a weakness where an application unintentionally reveals private data. In the context of CVE-2026-42164, this means a flaw in the Text block feature allows a user to access stored content that should remain private, effectively bypassing the expected boundaries between different text sections or user files.

How can an attacker trigger this vulnerability?

An attacker triggers the vulnerability by submitting a specifically crafted network call to the Text block functionality. It is important to note that this is not caused by standard text editing or legitimate user interactions; it requires the deliberate construction of an input that forces the system to incorrectly recall and display backed-up content from a separate text section.

Do I need to worry if my Mahara instance is internal?

While internal instances may be less accessible to the general public, Halo Surface Signal notes that Mahara is typically deployed as a public-facing web application for easy access by students and staff. Because the vulnerability exists in a core, reachable component of the web interface, any deployment accessible over a network carries a risk that should be evaluated.

When should I take action for this vulnerability?

You should act immediately by identifying all Mahara instances within your environment. Verify whether your specific version is affected and confirm who is responsible for the platform's security. Prioritize these actions based on the importance of the data stored in your ePortfolio system and plan your next steps for applying patches or updates as they become available.

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.