Vulnerability · Published Sep 22, 2026 · Assigned by GitHub_M

CVE-2026-77257MCP Atlassian: HTTP upload tools accept arbitrary server-local file paths

High 8.3

In plain English

A high-severity path traversal in mcp-atlassian from sooperset. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.3High

Exploit odds (30 days)0.4%top 67.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, HTTP-exposed Jira and Confluence upload tools pass a caller-provided file_path to local file operations without restricting it to the workspace. A remote MCP caller with tool access can cause the server to read sensitive local files and upload them as Atlassian attachments. The advisory traces the vulnerable input and processing flow through streamable-http, upload_attachment, and file_path, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	mcp-atlassian	0.22.0	GHSA-mrq8-fv7v-hhjg
PyPI	mcp-atlassian	0.22.0	PYSEC-2026-4098

Affected products (as reported)

Vendor	Product	Versions
sooperset	mcp-atlassian	< 0.22.0

Weakness: CWE-22 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N

References

https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-mrq8-fv7v-hhjg x_refsource_CONFIRM
https://github.com/sooperset/mcp-atlassian/pull/1448 x_refsource_MISC
https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 x_refsource_MISC
https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 x_refsource_MISC