# CVE-2026-77258: MCP Atlassian path traversal in attachment upload

Source: https://junglewise.ai/threats/cve-2026-77258-mcp-atlassian-is-a-model-context-protocol-mcp-server-for  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-22. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-77258 · Severity: high · CVSS 7.7 · Published 2026-09-22

MCP Atlassian is a server that extends Atlassian Confluence and Jira with AI-assisted capabilities. A vulnerability in versions prior to 0.22.0 allows authenticated users to upload arbitrary files from the server's filesystem as attachments, enabling disclosure of sensitive data like configuration files, credentials, and source code readable by the server process.

Technologies: [mcp-atlassian (PyPI)](https://junglewise.ai/threats/technologies/mcp-atlassian), [Sooperset Mcp-Atlassian](https://junglewise.ai/threats/technologies/sooperset-mcp-atlassian). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi), [Sooperset](https://junglewise.ai/threats/vendors/sooperset).

## Quick answers

**Is CVE-2026-77258 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-77258 being exploited in the wild.

**How severe is CVE-2026-77258?** High severity, with a CVSS score of 7.7, published 22 September 2026.

**Which products and versions are affected?** mcp-atlassian (PyPI) ECOSYSTEM:introduced=0,fixed=0.22.0; Sooperset Mcp-Atlassian before 0.22.0.

**Is there a fix for CVE-2026-77258?** Yes. mcp-atlassian (PyPI): upgrade to 0.22.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-77258 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-77258?** Check whether you run mcp-atlassian (PyPI) or Sooperset Mcp-Atlassian at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- mcp-atlassian (PyPI): upgrade to 0.22.0 or later

  ```sh
  pip install "mcp-atlassian>=0.22.0"
  ```


## Technical details

The upload_attachment function in Confluence and Jira modules accepts caller-controlled file paths and opens them without path validation, allowing directory traversal via absolute paths or ../ sequences. An authenticated MCP caller can supply any file path readable by the server process, which is then uploaded and disclosed as an attachment. The fix validates all file paths against the workspace using a validate_safe_path function, confining uploads to the working directory.

## Affected products

- sooperset mcp-atlassian before 0.22.0

## Identifiers

- CVE-2026-77258
- GHSA-93xw-j965-9mx3
- PYSEC-2026-4088

## Timeline

- 2026-09-22: disclosed
- 2026-07-10: patched

## References

- [https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460](https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460)
- [https://github.com/sooperset/mcp-atlassian/pull/1448](https://github.com/sooperset/mcp-atlassian/pull/1448)

## Related threats

- [sooperset mcp-atlassian path traversal in validate_safe_path](https://junglewise.ai/threats/cve-2026-124503-a-vulnerability-was-identified-in-sooperset-mcp-atlassian-up-to)
- [Atlassian MCP reflected XSS in OAuth setup callback handler](https://junglewise.ai/threats/cve-2026-77272-atlassian-mcp-reflected-xss-in-oauth-setup-callback-handler)
- [Atlassian MCP path traversal in upload_attachment allows arbitrary file read](https://junglewise.ai/threats/cve-2026-77269-atlassian-mcp-path-traversal-in-upload-attachment-allows)
- [Atlassian MCP insecure OAuth token file permissions](https://junglewise.ai/threats/cve-2026-77268-atlassian-mcp-insecure-oauth-token-file-permissions)
- [MCP Atlassian path traversal in upload_attachment](https://junglewise.ai/threats/cve-2026-77266-mcp-atlassian-path-traversal-in-upload-attachment)