Path Traversal in mcp-atlassian (CVE-2026-77259)
Summary
Path traversal in mcp-atlassian (CVE-2026-77259). Confidential information can be exposed externally. Exploitable via confluence_upload_attachment. Mitigation: upgrade to 0.22.0 or later.
Original description
The description as published by the source.
Summary
Missing path validation in confluence_upload_attachment allows any authenticated MCP client to read arbitrary files from the server filesystem and exfiltrate their contents to Confluence. On Linux deployments, /proc/self/environ yields all runtime secrets in a single call.
Details
AttachmentsMixin.upload_attachment() in src/mcp_atlassian/confluence/attachments.py opens the caller-supplied file_path with no boundary check:
# line 477
files = {"file": (filename, open(file_path, "rb"))}
The download path was correctly hardened in GHSA-xjgw-4wvw-rgm4 via validate_safe_path() (lines 223, 272). That fix was not applied to the upload path, leaving it completely unguarded. The MCP tool layer (servers/confluence.py:1295) passes file_path verbatim with no additional sanitization.
PoC
# 1. Prepare target file (macOS demo; on Linux use /proc/self/environ directly)
cp ~/.aws/credentials /tmp/diagram.png
# 2. Call the MCP tool
confluence_upload_attachment(
content_id = "",
file_path = "/tmp/diagram.png"
)
# 3. Download attachment from Confluence — contains raw credentials
Tested on mcp-atlassian 0.21.1 against live Confluence Cloud. Attachment confirmed uploaded and retrieved with full credential content intact.
Impact
Any MCP client with edit access to one Confluence page can read arbitrary files from the server process. On shared/Docker deployments, /proc/self/environ exposes all users' API…
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-2026-77259 has been found in mcp-atlassian.
Attackers can target a specific entry point like confluence_upload_attachment over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.7/10.
What to do: upgrade mcp-atlassian to 0.22.0 or later.
If unsure, ask your IT team or search "mcp-atlassian CVE-2026-77259" on the vendor's site.
CVE-2026-77259 (mcp-atlassian) — CWE-22 / CVSS v3 7.7
Attack vector: remote (network-reachable) / no user interaction
Attack surface: confluence_upload_attachment / file_path
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 confluence_upload_attachment.
Check the vendor advisory for the affected versions of mcp-atlassian. Attack surface: confluence_upload_attachment / file_path.
Severity: High (CVSS 7.7/10). 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 request patterns matching this CVE's known IOCs. 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。 -
2Apply 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を含めること。
-
3Post-deployment verification verify
Confirm patched version is live in production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。本番ではアクセスログ・WAF 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