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CVE-2026-77253

Mcp-atlassian Mcp Atlassian path traversal

7.1 HIGHPublic exploitEPSS 0.37%
  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, Jira and Confluence attachment upload tools accept arbitrary local filesystem paths and send the selected bytes to Atlassian. In HTTP or multi-user deployments, a caller can cross the client-to-server filesystem boundary and disclose configuration, credentials, mounted secrets, or other files readable by the MCP process. The advisory traces the vulnerable input and processing flow through jira_upload_attachment, confluence_upload_attachment, file_path, and server-local filesystem, 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
IntegrityLow
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

Affected products

Mcp-atlassian Mcp Atlassian< 0.22.0

Frequently asked

Is CVE-2026-77253 being actively exploited?

CVE-2026-77253 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.37%.

How severe is CVE-2026-77253?

CVE-2026-77253 has a CVSS 3.1 base score of 7.1, rated high. EPSS estimates a 0.37% probability of exploitation.

Which products are affected by CVE-2026-77253?

Affected products include Mcp-atlassian Mcp Atlassian.

How do I fix CVE-2026-77253?

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-2026-77253 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.