CVE-2026-77253

MCP Atlassian: Jira and Confluence attachment upload tools can read arbitrary server-local files

HIGH
7.1
CVSS Score
Published: September 22, 2026 at 06:10 PM UTC
Updated: September 28, 2026 at 01:23 PM UTC
2 products affected across 2 vendorsMcp AtlassianAtlassian Mcp Atlassian

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Severity
HIGH7.1
Exploit prediction
EPSS 0.4%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.22.0
Affected range stops below 0.22.0, so it looks safe — our inference, not a vendor statement
v < 0.22.0
Affected range stops below 0.22.0, so it looks safe — our inference, not a vendor statement

References (4)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-vc25-24vv-fxxm
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/sooperset/mcp-atlassian/pull/1448
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.1HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-22

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