CVE-2026-77262 sooperset CVE debrief

Who should care

Defenders managing Confluence and Jira deployments using MCP Atlassian, particularly those responsible for system updates and security patches, should assess exposure, verify affected systems, and remediate by updating to version 0.22.0 or later. Operators of affected platforms and security teams should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Why it matters

CVE-2026-77262 allows attackers to upload arbitrary files to Confluence via MCP Atlassian's confluence_upload_attachment function. Defenders should assess exposure, verify affected systems, and remediate by updating to version 0.22.0 or later.

• Potential for arbitrary file uploads to Confluence
• Risk of unauthorized data access or modification
• Need for verification of affected systems and remediation
• Importance of updating MCP Atlassian to version 0.22.0 or later

Technical summary

The confluence_upload_attachment function in MCP Atlassian allows an attacker-controlled file_path, enabling traversal outside the workspace and upload of arbitrary server-readable files to Confluence. This issue is fixed in version 0.22.0. Defenders should assess exposure, particularly those managing Confluence and Jira deployments, and verify if their systems are affected and remediated. The advisory traces the vulnerable input and processing flow through confluence_upload_attachment, file_path, and CVE-2026-27825, which identify the affected entry points, controls, and code paths.

Defensive priority

High priority for Confluence and Jira deployments using MCP Atlassian versions prior to 0.22.0; verify and remediate vulnerable systems.

Recommended defensive actions

• Assess exposure for Confluence and Jira deployments using MCP Atlassian versions prior to 0.22.0
• Verify if systems are affected and remediated
• Update MCP Atlassian to version 0.22.0 or later
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The advisory and CVE details indicate a vulnerability in MCP Atlassian's confluence_upload_attachment function, allowing file path traversal and arbitrary file uploads. The issue is fixed in version 0.22.0.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.