{"id":"CVE-2026-77246","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-77246","generatedAt":"2026-10-28T03:58:18.216Z","title":"Prior to 0.22.0, an HTTP transport deployment with READ_ONLY_MODE=false accepts a request without an Authorization identity and permits attacker-controlled Atlassian service headers, including X-Atlassian-Confluence-Url, to select a public attacker…","description":"MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, an HTTP transport deployment with READ_ONLY_MODE=false accepts a request without an Authorization identity and permits attacker-controlled Atlassian service headers, including X-Atlassian-Confluence-Url, to select a public attacker hostname or one allowed by MCP_ALLOWED_URL_DOMAINS. A caller can then invoke confluence_upload_attachment or the Jira attachment variant in src/mcp_atlassian/jira/attachments.py with a server-local file_path and cause the MCP process to send the file to the selected attachment endpoint. This issue is fixed in version 0.22.0.","published":"2026-09-22T19:16:49.000Z","lastModified":"2026-09-28T14:31:10.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":8.6,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N"},"cwe":["CWE-22","CWE-200","CWE-441"],"affected":["mcp-atlassian/mcp atlassian"],"epss":{"score":0.00471,"percentile":0.40549,"date":"2026-10-27","history":[{"date":"2026-09-23","score":0.00298,"percentile":0.22676}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.47%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"scored","label":"Newly scored","at":"2026-09-28T15:30:20.000Z","detail":{"from":"7.4","score":"8.6","severity":"HIGH","fromSeverity":"HIGH"},"summary":"Now scored CVSS 8.6 HIGH (was 7.4)."},{"kind":"new","label":"New CVE","at":"2026-09-22T19:16:49.000Z","detail":{"score":"7.4","severity":"HIGH","publishedAt":"2026-09-22T19:16:48.730Z"},"summary":"New CVE, high severity (CVSS 8.6)."}],"references":[{"url":"https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/sooperset/mcp-atlassian/pull/1448","tags":["Issue Tracking","Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-wv8v-v4c5-v75j","tags":["Exploit","Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-wv8v-v4c5-v75j","tags":["Exploit","Vendor Advisory"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-77246","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}