{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","favicon":"https://feed.craftedsignal.io/favicon-32x32.png","feed_url":"https://feed.craftedsignal.io/tags/cve-2026-77253/feed.json","home_page_url":"https://feed.craftedsignal.io/","icon":"https://feed.craftedsignal.io/apple-touch-icon.png","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[{"cvss":7.1,"id":"CVE-2026-77253"}],"_cs_exploited":true,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["mcp-atlassian (\u003c 0.22.0)"],"_cs_severities":["high"],"_cs_tags":["path-traversal","data-exfiltration","mcp","cve-2026-77253"],"_cs_type":"threat","_cs_vendors":[],"content_html":"\u003cp\u003eThe mcp-atlassian package (prior to version 0.22.0) is vulnerable to an arbitrary file read vulnerability (CVE-2026-77253) due to a lack of path validation in its Jira and Confluence attachment upload tools. When an MCP server is deployed in a multi-user or HTTP-exposed environment, an attacker with write-tool access can trigger the upload of arbitrary local files accessible to the MCP process. The tools receive a 'file_path' parameter, perform minimal existence checks, and directly open the file for reading before transmitting it to the configured Jira or Confluence instance as an attachment. This vulnerability potentially allows for the exfiltration of sensitive server-side assets, including environment variables, service account credentials, mounted secrets, and source code. Defenders should immediately audit MCP deployments for exposure and upgrade to version 0.22.0 or later, which introduces necessary path validation logic.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe MCP server is deployed with HTTP access enabled, allowing remote interaction with its defined toolset.\u003c/li\u003e\n\u003cli\u003eAn attacker identifies the 'upload_attachment' (Confluence) or 'update_issue' (Jira) tool within the mcp-atlassian configuration.\u003c/li\u003e\n\u003cli\u003eThe attacker crafts a request to the MCP server invoking the write-capable attachment tool.\u003c/li\u003e\n\u003cli\u003eThe attacker provides a target local file path (e.g., '/etc/passwd' or a local secret file) as the 'file_path' or 'attachments' argument.\u003c/li\u003e\n\u003cli\u003eThe mcp-atlassian library receives the path and fails to invoke 'validate_safe_path()' or verify the file against an allowed directory list.\u003c/li\u003e\n\u003cli\u003eThe server process opens the specified file using Python's 'open(file_path, \u0026quot;rb\u0026quot;)'.\u003c/li\u003e\n\u003cli\u003eThe process reads the file contents and transmits them as an attachment to the Jira issue or Confluence page associated with the authenticated user.\u003c/li\u003e\n\u003cli\u003eThe attacker retrieves the exfiltrated sensitive content from the Jira or Confluence instance.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows for unauthorized exfiltration of sensitive local data to enterprise issue tracking systems. This represents a significant risk in containerized or cloud-hosted environments where MCP servers may have access to mounted secrets, Kubernetes service account tokens, or local configuration files. Depending on the server's permissions, an attacker could extract credentials to pivot into deeper infrastructure or exfiltrate intellectual property via Jira and Confluence attachments.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eUpgrade the 'mcp-atlassian' package to version 0.22.0 or later immediately to resolve CVE-2026-77253.\u003c/li\u003e\n\u003cli\u003eIf an immediate upgrade is not possible, enable 'READ_ONLY_MODE=true' on all MCP server instances to prevent the invocation of vulnerable write tools.\u003c/li\u003e\n\u003cli\u003eImplement strict network access controls for MCP servers exposed over HTTP; restrict access to authorized users or service identities only.\u003c/li\u003e\n\u003cli\u003eConduct a review of file system permissions for the user account running the MCP server process to minimize the impact of potential path traversal, ensuring it cannot read sensitive configuration or secret files.\u003c/li\u003e\n\u003cli\u003eAudit Jira and Confluence audit logs for anomalous attachment uploads from the MCP-associated service account.\u003c/li\u003e\n\u003c/ol\u003e\n","date_modified":"2026-09-23T07:55:16Z","date_published":"2026-09-23T07:55:16Z","id":"https://feed.craftedsignal.io/briefs/2026-09-mcp-atlassian-path-traversal/","summary":"The mcp-atlassian package contains a path traversal vulnerability allowing an authenticated MCP caller to exfiltrate arbitrary server-local files to Jira or Confluence via attachment upload tools.","title":"Arbitrary File Read Vulnerability in mcp-atlassian","url":"https://feed.craftedsignal.io/briefs/2026-09-mcp-atlassian-path-traversal/"}],"language":"en","title":"CraftedSignal Threat Feed - Cve-2026-77253","version":"https://jsonfeed.org/version/1.1"}