CVE-2026-77252 sooperset CVE debrief

Who should care

Defenders responsible for Atlassian products and MCP Atlassian server should assess exposure and apply the patch to prevent potential unauthorized access. This includes operators, platform administrators, vulnerability management teams, and security teams who need to verify exposure and apply the patch to prevent potential unauthorized access.

Why it matters

The vulnerability in MCP Atlassian allows an attacker to bypass administrator-configured allowlists, potentially leading to unauthorized access. Defenders should prioritize verifying exposure and applying the patch.

• Verify exposure by checking the current version of MCP Atlassian.
• Apply the patch to prevent potential unauthorized access.
• Review administrator-configured allowlists and adjust them as necessary.

Technical summary

The vulnerability in MCP Atlassian allows an attacker to bypass administrator-configured allowlists by manipulating the projects_filter and spaces_filter arguments. This can lead to searching projects or spaces outside the intended boundary. The vulnerability can be exploited through JIRA_PROJECTS_FILTER, CONFLUENCE_SPACES_FILTER, projects_filter, spaces_filter, SearchMixin.search_issues, and SearchMixin.search entry points. The issue is fixed in version 0.22.0, and patches are available. Defenders should prioritize verifying exposure and applying the patch to prevent potential unauthorized access.

Defensive priority

Defenders should prioritize verifying exposure and applying the patch to prevent potential unauthorized access.

Recommended defensive actions

• Verify exposure by checking the current version of MCP Atlassian and identifying if it is prior to 0.22.0.
• Apply the patch by upgrading to version 0.22.0 or later.
• Review administrator-configured allowlists and adjust them as necessary.
• 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 supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Evidence notes

The vulnerability is described in the CVE record and NVD vulnerability detail page. The issue is fixed in version 0.22.0, and patches are available. The CVE record was published on 2026-09-22T18:17:18.047Z and has not been modified since then. The official CVE Program record and NIST NVD detail page provide source-provided CVE metadata and source-specific vulnerability assessment.

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.