Path Traversal in mcp-atlassian (CVE-2026-77266)
Summary
Path traversal in mcp-atlassian (CVE-2026-77266). Confidential information can be exposed externally. Exploitable via upload_attachment. Mitigation: upgrade to 0.22.0 or later.
Original description
The description as published by the source.
Summary
The upload_attachment functions in both the Jira and Confluence modules accept a user-controlled file_path parameter and open the specified file for reading without calling validate_safe_path(). An authenticated MCP client can supply an arbitrary path such as /etc/passwd or /proc/self/environ, causing the server process to read and transmit the file's contents to the remote Atlassian instance as an attachment.
This is an incomplete fix relative to GHSA-xjgw-4wvw-rgm4: the download_attachment and download_issue_attachments paths were hardened with validate_safe_path(), but the upload direction was left unguarded in both the Jira and Confluence modules.
Details
Affected functions:
| File | Function | Line |
|---|---|---|
src/mcp_atlassian/jira/attachments.py |
upload_attachment() |
~372–415 |
src/mcp_atlassian/confluence/attachments.py |
upload_attachment() |
~62–108 |
src/mcp_atlassian/confluence/attachments.py |
_upload_attachment_direct() |
~476–477 |
Jira — vulnerable code path (jira/attachments.py):
def upload_attachment(self, issue_key: str, file_path: str) -> dict:
...
if not os.path.isabs(file_path):
file_path = os.path.abspath(file_path) # resolves relative paths
if not os.path.exists(file_path): # confirms file exists
...
# ⚠ validate_safe_path() is NEVER called here
filename = os.path.basename(file_path)
with o…
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-2026-77266 has been found in mcp-atlassian.
Attackers can target a specific entry point like upload_attachment over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 6.5/10.
What to do: upgrade mcp-atlassian to 0.22.0 or later.
If unsure, ask your IT team or search "mcp-atlassian CVE-2026-77266" on the vendor's site.
CVE-2026-77266 (mcp-atlassian) — CWE-22 / CVSS v3 6.5
Attack vector: remote (network-reachable) / no user interaction
Attack surface: upload_attachment / file_path / download_attachment / download_issue_attachments
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 upload_attachment.
Check the vendor advisory for the affected versions of mcp-atlassian. Attack surface: upload_attachment / file_path / download_attachment / download_issue_attachments.
Severity: Medium (CVSS 6.5/10). 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
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