External risk intelligence

MCP Atlassian Improper Identity Verification Allows Unauthorized Tool Invocation.

CVE advisorySeverity: CRITICAL (CVSS 10.0)

CVE-2026-77244

The Model Context Protocol (MCP) server facilitates communication between AI models and internal tools. While it functions as a network service that could be exposed, it is typically deployed as a component within a local or developer-oriented AI development environment rather than a standard public-facing web service or internet gateway.

Authentication Bypass

Mcp Atlassian Mcp Atlassian

before 0.22.0

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

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This critical vulnerability in the MCP Atlassian server, which supports Atlassian products like Confluence and Jira, allows unauthenticated network access to invoke tools and perform actions using existing operator credentials. Its exposure can be external, meaning it could be accessible over a network. The main concern is confirming its relevance and exposure within our environment.

Unauthenticated access to Atlassian tools.
Could allow unauthorized actions within our systems.
Verify if this tool is used and exposed.

Attack Path

How an attacker could exploit the issue

An attacker who can reach the MCP Atlassian server can bypass authentication and execute actions on Atlassian tools like Jira or Confluence. This is because the server, before version 0.22.0, would accept requests without verifying the user's identity and would then use the operator's stored credentials for any subsequent actions. This allows an unauthenticated network client to perform read and write operations on Atlassian products using the permissions of the operator.

Network access to MCP endpoint required.
Unverified identity allows credential fallback.
Unauthorized tool access and data manipulation.

Live Threat

Current exploitation, exposure, and threat context

When supported by the advisory, a network client that can reach the MCP endpoint could invoke Atlassian tools as the operator, potentially affecting read and write operations available to that account.

Atlassian tool operations could be impacted.
Unauthenticated requests may trigger unauthorized actions.
Unauthorized data access and modification may occur.

Operational Fix

Recommended remediation, mitigation, and detection steps

The MCP Atlassian server, integrated with Jira and Confluence, presents a critical risk where unauthenticated network clients can execute operations as the configured operator. Identifying instances of this server, verifying their network reachability and business criticality, and pinpointing the accountable system owner are the immediate first steps. Remediation planning should then be risk-based, considering the potential impact of unauthorized access to Atlassian tools.

The platform or application owner should lead remediation.
Verify MCP Atlassian server reachability and criticality.
Plan remediation based on asset owner engagement.

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 mcp-atlassian software used for?

mcp-atlassian is a Model Context Protocol (MCP) server that acts as a bridge between AI models and Atlassian applications like Jira and Confluence. It allows AI systems to interact with these platforms, enabling users to programmatically query, read, or update project management and documentation data through the protocol.

How does CVE-2026-77244 compromise system security?

This vulnerability involves improper authentication and missing authorization controls (CWE-287, CWE-862). In affected versions, the server fails to verify the identity of the person making a request. Consequently, it defaults to using the operator's saved credentials to execute tasks, allowing unauthorized parties to perform actions as if they were the legitimate, authenticated user.

What actions trigger this vulnerability?

An attacker needs network access to the MCP endpoint to trigger the flaw. Simply sending a request to the server is sufficient, as the software lacks checks to validate the requester. It is important to note that internal application logic processing, such as operations performed by a correctly authenticated internal service already using the protocol legitimately, does not inherently cause this specific flaw; the risk arises specifically from unverified external network connections.

Is my environment at risk from this vulnerability?

According to Halo Surface Signal, this software is often used in local or developer-oriented AI environments rather than as a public-facing gateway. You should prioritize checking if your deployment is reachable over a broader network. If the service is restricted to isolated local machine access, the risk level is lower than if it is reachable via internal or external network segments.

How do I secure my infrastructure against this threat?

The primary response is to update to version 0.22.0 or later, which corrects the identity verification process. Until you can update, identify where this server is running in your environment and restrict network access to the MCP endpoint to only known, authorized entities to prevent unauthorized tool invocation.

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.