mediumCVSS 6.5Vulnerability

CVE-2026-77269

### Summary The `confluence_upload_attachment` and `confluence_upload_attachments` MCP tools accept a `file_path` parameter and do not validate that the path is confined to an allowed directory before opening the file. An attacker who can call these tools can read any file accessible to the MCP server process (SSH keys, .env files, API credentials) and exfiltrate it by uploading it to Confluence. Note: The Jira `upload_attachment` mixin method in `jira/attachments.py` has the same missing validation, but it is NOT registered as an MCP tool in `servers/jira.py` and is therefore not currently reachable via MCP. It should still be patched to prevent future exposure if Jira upload tools are added. This is an incomplete fix for CVE-2026-27825. That CVE was patched by adding `validate_safe_path()` to download operations (v0.17.0). The same protection was not applied to upload operations. ### Details `validate_safe_path()` is imported in both `confluence/attachments.py` and `jira/attachments.py` and is correctly called in all download functions. It is absent from the Confluence upload functions (which are exposed as MCP tools) and from the Jira upload mixin methods (which are not currently registered as MCP tools but should still be patched). **Download (protected — correctly patched):** ```python # confluence/attachments.py:222-223 validate_safe_path(target_path) # resolves symlinks + checks is_relative_to(cwd) ``` **Upload (vulnerable — not patched):** ```python # confluence/attachments.py:64-79 — NO validate_safe_path() call if not os.path.isabs(file_path): file_path = os.path.abspath(file_path) # normalizes but does NOT restrict # ... files = {"file": (filename, open(file_path, "rb"))} # opens arbitrary file ``` Same pattern in `jira/attachments.py:386`. ### Proof of Concept ```python # Call via MCP client await session.call_tool("confluence_upload_attachment", { "content_id": "12345", "file_path": "/home/user/.ssh/id_rsa" # absolute path — no

Properties

ghsa_id
GHSA-h7wj-5v37-59r2
severity
medium
summary
MCP Atlassian: Path traversal in upload_attachment allows arbitrary file read (incomplete fix for CVE-2026-27825)
cvss_score
6.5
cve_id
CVE-2026-77269
cvss_vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
signal_observed_at
2026-09-23T04:35:57+00:00
is_ghsa_only
false
ghsa_published
2026-09-22T20:35:03Z
source_url
https://github.com/advisories/GHSA-h7wj-5v37-59r2
ghsa_updated
2026-09-22T20:35:05Z

Related Entities (4)

VULNERABLE_TO (1)

[Software]pip/mcp-atlassian

HAS_WEAKNESS (1)

[Weakness]Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

REPORTED_BY (1)

[Source]GitHub Advisory Database

AFFECTS (1)

[Software]pip/mcp-atlassian

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CVE-2026-77269 (CVSS 6.5) — Ninja Signal Threat Intelligence | Ninja Signal