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CVE-2026-77243

Mcp-atlassian Mcp Atlassian broken access control

8.8 HIGHPublic exploitEPSS 0.32%
  1. Published22 Sept 2026

Description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, ENABLED_TOOLS and TOOLSETS are applied when tools are listed but are not rechecked when a tools/call request is dispatched. A client that knows a hidden tool name can directly invoke excluded read, write, or delete tools despite the operator's configured least-privilege restrictions. The advisory traces the vulnerable input and processing flow through ENABLED_TOOLS, TOOLSETS, tools/list, tools/call, and _call_tool_mcp, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Mcp-atlassian Mcp Atlassian< 0.22.0

Remediation

Fixed in
Mcp-atlassian Mcp Atlassian≥ 0.22.0

References

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Frequently asked

Is CVE-2026-77243 being actively exploited?

CVE-2026-77243 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.32%.

How severe is CVE-2026-77243?

CVE-2026-77243 has a CVSS 3.1 base score of 8.8, rated high. EPSS estimates a 0.32% probability of exploitation.

Which products are affected by CVE-2026-77243?

Affected products include Mcp-atlassian Mcp Atlassian.

How do I fix CVE-2026-77243?

Upgrade affected software to a fixed version, for example Mcp-atlassian Mcp Atlassian 0.22.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-77243 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.