mcp-atlassian < 0.17.0 - Server-Side Request Forgery

MCP Atlassian 0.17.0 contains a server-side request forgery caused by improper validation of custom HTTP headers in the HTTP middleware, letting unauthenticated attackers force outbound requests to arbitrary URLs, exploit requires access to the mcp-atlassian HTTP endpoint. id: CVE-2026-27826 info...

CVE-2026-77261

creationtimestamp| type| source ---|---|--- 2026-09-22 22:35:52+00:00| published-proof-of-concept| https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6529-c226-h328...

CVE-2026-77268

creationtimestamp| type| source ---|---|--- 2026-09-22 22:35:49+00:00| published-proof-of-concept| https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-4596-2p6p-28cv...

CVE-2026-77272

creationtimestamp| type| source ---|---|--- 2026-09-22 22:35:45+00:00| published-proof-of-concept| https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g2r2-3j32-j27x...

MCP Atlassian: Arbitrary file read/exfiltration via upload_attachment missing validate_safe_path()

Summary The uploadattachment method in confluence/attachments.py reads and uploads arbitrary local files to Confluence without calling validatesafepath. Both download methods downloadattachment at line 223, downloadcontentattachments at line 272 correctly call validatesafepath before writing file...

MCP Atlassian: OAuth fallback token storage writes plaintext access and refresh tokens with group-readable permissions

Summary When OAuth tokens are saved, MCP Atlassian always writes a plaintext fallback copy under /.mcp-atlassian/oauth-.json. The fallback file is created with the process default umask rather than restrictive permissions. In this environment the file was created as mode 0664, exposing access and...

MCP Atlassian: Incomplete fix for GHSA-7r34-79r5-rcc9: redirect-based SSRF via unhooked requests session in Jira user-permission lookup

Summary The fix for the SSRF vulnerability tracked as GHSA-7r34-79r5-rcc9 / CVE-2026-27826 is incomplete. That fix added two defenses: validateurlforssrf on the per-request X-Atlassian-Jira-Url / X-Atlassian-Confluence-Url headers blocking a directly-internal base URL, and a redirect-validation...

MCP Atlassian: Arbitrary server-local file upload to Jira/Confluence attachments via unrestricted file_path parameters

Summary The Jira and Confluence attachment upload tools accept caller-controlled file path parameters and read those paths from the MCP server's local filesystem before uploading the file as an Atlassian attachment. In local stdio deployments, this can expose files readable by the user's MCP...

[mcp-atlassian] Authentication bypass in HTTP transport: AtlassianOpaqueTokenVerifier accepts any non-empty token

Description mcp-atlassian deploys in two common patterns: Pattern A single-user, server-side credentials: operator sets JIRAUSERNAME + JIRAAPITOKEN or CONFLUENCEUSERNAME + CONFLUENCEAPITOKEN in environment variables. Server uses these to call Jira/Confluence. This is the documented quickstart...

MCP Atlassian: SSRF Protection Bypass

Environment - Project: sooperset/mcp-atlassian - Affected function: validateurlforssrf - Affected path: header-based Jira/Confluence URL authentication flow - Tested endpoint: POST /mcp - Tested version: 2.14.5 Description The SSRF protection in validateurlforssrf can be bypassed with a URL...

MCP Atlassian: Incomplete path traversal fix allows intra-CWD module overwrite and RCE (bypass of GHSA-xjgw-4wvw-rgm4)

Summary The path traversal fix introduced in v0.17.0 GHSA-xjgw-4wvw-rgm4 is incomplete. validatesafepath is called without an explicit basedir, defaulting to os.getcwd. In standard container deployments the process CWD is the application directory e.g. /app, so paths within that directory,...

mcp-atlassian has an incomplete SSRF remediation

Summary The UserTokenMiddleware extracts URLs from X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url HTTP headers and passes them directly to API client constructors without any SSRF validation. Affected Package - Ecosystem: PyPI - Package: mcp-atlassian - Affected versions: all versions before...

MCP Atlassian: Reflected XSS in OAuth Setup Callback Handler

Summary The OAuth 2.0 setup wizard's local callback HTTP server reflects the error query parameter directly into an HTML response without any sanitization or encoding. An attacker can craft a malicious callback URL containing JavaScript in the error parameter that executes in the victim's browser...

MCP Atlassian: Path Traversal / Arbitrary File Read in confluence_upload_attachment MCP tool (incomplete fix of GHSA-xjgw-4wvw-rgm4)

Summary mcp-atlassian exposes an MCP tool confluenceuploadattachment whose filepath argument is passed directly to openfilepath, "rb" without any path validation. An attacker able to invoke the tool can read arbitrary files readable by the server process and exfiltrate them into a multipart uploa...

MCP Atlassian: Insecure File Permissions on OAuth Token Storage

Summary The OAuth token fallback file storage in OAuthConfig.savetokenstofile creates token files containing access tokens, refresh tokens, and cloud IDs with default filesystem permissions typically 0644 on Linux, world-readable. Any local user on a shared system can read these files to obtain...

MCP Atlassian: Arbitrary file read via confluence_upload_attachment allows exfiltration of server credentials

Summary Missing path validation in confluenceuploadattachment 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...

MCP Atlassian: SSRF redirect protection missing for basic-auth and OAuth authentication branches

Summary makessrfsafehook blocks HTTP redirects to private/internal IPs by validating the Location header before the client follows a 3xx response. The problem is that this hook is only attached in one of three authentication branches — the header-PAT path. Basic auth and OAuth branches skip it...

MCP Atlassian: Arbitrary File Read via Upload Attachment Tools

Summary The upload attachment tools in both Confluence and Jira accept arbitrary file paths without path traversal validation. The uploadattachment methods read any file accessible to the server process and upload it to a Confluence page or Jira issue. Despite the existence of a validatesafepath...

MCP Atlassian: SSRF via DNS Rebinding in Header-Based Authentication Flow

Summary The SSRF protection for header-based authentication uses a validate-then-use pattern vulnerable to DNS rebinding. validateurlforssrf resolves the hostname via DNS and checks that the resolved IP is globally routable. However, the actual HTTP request happens later, during which the DNS...

MCP Atlassian: Path traversal in upload_attachment allows arbitrary file read and exfiltration via MCP tool call

Summary The uploadattachment functions in both the Jira and Confluence modules accept a user-controlled filepath parameter and open the specified file for reading without calling validatesafepath. An authenticated MCP client can supply an arbitrary path such as /etc/passwd or /proc/self/environ,...