CVE-2026-77270

MCP Atlassian: Arbitrary File Read via Upload Attachment Tools

MEDIUM
6.5
CVSS Score
Published: September 22, 2026 at 05:46 PM UTC
Updated: September 28, 2026 at 01:35 PM UTC
2 products affected across 2 vendorsMcp AtlassianAtlassian Mcp Atlassian

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.5%
SSVC
PoC

Description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the Jira and Confluence attachment upload tools treat caller-controlled file_path values as trusted server-local paths. The server opens the selected file and uploads it to an Atlassian issue or page, allowing an MCP caller with upload access to disclose any file readable by the server process. The advisory traces the vulnerable input and processing flow through confluence_upload_attachment, jira_upload_attachment, file_path, and open(file_path, "rb"), 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_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-f26r-j276-ggg4
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

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-22

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