MCP Atlassian: Path traversal in upload_attachment allows arbitrary file read and exfiltration via MCP tool call

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-77266
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-22 19:16:50 UTC
Updated2026-09-23 18:12:04 UTC
DescriptionMCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, upload_attachment accepts absolute paths and traversal sequences without constraining the resolved path to the server workspace. An MCP caller with attachment access can read a chosen server-local file and exfiltrate it through Jira or Confluence. The advisory traces the vulnerable input and processing flow through upload_attachment, file_path, and path traversal, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS: 0.004810000 probability, percentile 0.406170000 (date 2026-09-23)

Problem Types: CWE-22 | CWE-22 CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
3.1CNADECLARED6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Sooperset Mcp-atlassian affected < 0.22.0 Not specified

References

ReferenceSourceLinkTags
github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 [email protected] github.com
github.com/sooperset/mcp-atlassian/security/advisories/GHSA-mfv2-4wvm-9pgp 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c28... [email protected] github.com
github.com/sooperset/mcp-atlassian/pull/1448 [email protected] github.com
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