CVE-2026-77271 sooperset CVE debrief

Who should care

Defenders responsible for Confluence and Jira deployments using MCP Atlassian should assess exposure and prioritize remediation due to the potential for significant consequences if exploited. This vulnerability allows for code execution via module overwrite, which can have significant consequences if exploited, including attacker-selected writes within the working directory and bypassing remediation tracked as CVE-2026-27825. Defenders should verify .

Why it matters

CVE-2026-77271 allows for code execution via module overwrite in MCP Atlassian prior to version 0.22.0, affecting Confluence and Jira deployments. Defenders should prioritize verification of exposure and remediation.

• Code execution via module overwrite
• Potential for attacker-selected writes within the working directory
• Bypassing remediation tracked as CVE-2026-27825

Technical summary

MCP Atlassian, a Model Context Protocol server for Atlassian products, had a vulnerability prior to version 0.22.0 where the validate_safe_path function defaulted its base directory to the current working directory. Affected Confluence attachment call sites omitted the base directory, allowing attacker-selected writes within the working directory. This could lead to code execution when the application later imports the modified module. The vulnerability allows for code execution via module overwrite, affecting Confluence and Jira deployments. Defenders should prioritize verification of exposure and remediation for MCP Atlassian versions prior to 0.22.0.

Defensive priority

Defenders should prioritize verification of exposure and remediation for MCP Atlassian versions prior to 0.22.0, especially in Confluence and Jira deployments.

Recommended defensive actions

• Verify MCP Atlassian version and upgrade to 0.22.0 or later if necessary
• Review Confluence and Jira deployments for exposure
• Monitor for suspicious module imports and writes within the working directory
• 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. Review the
• technicalSummary
• whoShouldCare

Evidence notes

The CVE record and NVD entry provide details on the vulnerability in MCP Atlassian, which allows for code execution via module overwrite prior to version 0.22.0. The vulnerability is caused by the validate_safe_path function defaulting its base directory to os.getcwd(), and affected Confluence attachment call sites omitting base_dir, allowing attacker-selected writes within the working directory. This issue is fixed in version 0.22.0. Defenders should verify exposure and prioritize remediation, especially in Confluence and Jira The N

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.