Path Traversal in mcp-atlassian (CVE-2026-77246)
Summary
Path traversal in mcp-atlassian (CVE-2026-77246). Confidential information can be exposed externally. Exploitable via POST /mcp. Mitigation: upgrade to 0.22.0 or later.
Original description
The description as published by the source.
Summary
The mcp-atlassian server exposes an MCP tool (confluence_upload_attachment and the Jira attachment variant) that accepts an arbitrary server-side file path and opens it for upload without any path validation. When the server is deployed in HTTP transport mode (streamable-http or sse), a remote, unauthenticated attacker can supply attacker-controlled Atlassian service headers (X-Atlassian-Confluence-Url / X-Atlassian-Confluence-Personal-Token) to redirect the upload to an attacker-controlled endpoint, then pass an arbitrary file_path (e.g. /etc/passwd, ~/.env, SSH private keys, cloud credentials) to exfiltrate any file readable by the server process. No prior account, session token, or Authorization header is required. The vulnerability was confirmed through both static code analysis (Phase 1) and a live Docker-based proof-of-concept (Phase 2).
Details
Data flow (source → sink)
| Step | Location | Role |
|---|---|---|
| 1 | src/mcp_atlassian/servers/main.py:498-504 |
Middleware extracts X-Atlassian-Confluence-Url and X-Atlassian-Confluence-Personal-Token from incoming HTTP request headers. |
| 2 | src/mcp_atlassian/servers/main.py:584-595 |
When no Authorization header is present but service headers are, user_atlassian_auth_type is set to "pat", effectively bypassing authentication requirements. |
| 3 | src/mcp_atlassian/utils/urls.py:97-104 |
validate_url_for_ssrf blocks only localhost, RFC 1918… |
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-77246 has been found in mcp-atlassian.
Attackers can target a specific entry point like POST /mcp over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.4/10.
What to do: upgrade mcp-atlassian to 0.22.0 or later.
If unsure, ask your IT team or search "mcp-atlassian CVE-2026-77246" on the vendor's site.
CVE-2026-77246 (mcp-atlassian) — CWE-22 / CVSS v3 7.4
Attack vector: adjacent-network / unauthenticated / no user interaction
Attack surface: POST /mcp / Authorization header / confluence_upload_attachment / sse
Patched: 0.22.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Path traversal (CWE-22) exists in mcp-atlassian. Attackers reach the vulnerable code path via POST /mcp without authentication.
Check the vendor advisory for the affected versions of mcp-atlassian. Attack surface: POST /mcp / Authorization header / confluence_upload_attachment / sse.
Severity: High (CVSS 7.4/10). Confidential information can be exposed externally.
Update to 0.22.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /mcp requests with malformed payloads or SQL meta-characters. Run grep -r 'mcp-atlassian' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'mcp-atlassian' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
mcp-atlassianを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'POST /mcp' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /mcpへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade mcp-atlassian to 0.22.0ステージング環境で 0.22.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against POST /mcp on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- package github.com
- package pypi.org
- web github.com
- web github.com
- web github.com
- web github.com