MCP Atlassian: Arbitrary File Read via Upload Attachment Tools (CVE-2026-77270) | HOL Guard CVE

Medium · CVSS 6.5CVE-2026-77270

MCP Atlassian: Arbitrary File Read via Upload Attachment Tools

Answer in brief

CVE-2026-77270 records a Medium severity (CVSS 6.5) vulnerability in MCP Atlassian: Arbitrary File Read via Upload Attachment Tools. The current sources do not mark it as known exploited. The current feed maps sooperset/mcp-atlassian (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 22, 2026Updated Sep 22, 2026Source checked Sep 22, 2026First seen by HOL Sep 22, 2026Material review Sep 22, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.5
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 6.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps sooperset/mcp-atlassian (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
sooperset/mcp-atlassiangeneric	<0.22.0	0.22.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for sooperset/mcp-atlassian.
Review the reported fix. Update sooperset/mcp-atlassian to 0.22.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 22, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.