CVE-2026-77255

{"id": "CVE-2026-77255", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-77255", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-09-26T00:00:16.341441Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 8.6, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 4.0, "exploitabilityScore": 3.9}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "sooperset", "product": "mcp-atlassian", "versions": [{"status": "affected", "version": "< 0.22.0"}]}]}], "published": "2026-09-22T19:16:49.850", "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-2xj6-xx86-cwwc", "tags": ["Exploit", "Vendor Advisory"], "source": "security-advisories@github.com"}, {"url": "https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-2xj6-xx86-cwwc", "tags": ["Exploit", "Vendor Advisory"], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-22"}, {"lang": "en", "value": "CWE-441"}]}], "descriptions": [{"lang": "en", "value": "MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the Jira update_issue attachments argument is converted into local paths and routed to the attachment upload implementation without workspace validation. A caller can make the MCP server read arbitrary local files and attach them to a Jira issue, using the server as a confused deputy to exfiltrate the contents. The advisory traces the vulnerable input and processing flow through jira update_issue, attachments, upload_attachment, and file_path, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0."}], "lastModified": "2026-09-29T13:41:25.460", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:mcp-atlassian:mcp_atlassian:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "5B21EB9C-719D-42B9-8F6D-BE4EDC5D39AD", "versionEndExcluding": "0.22.0"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}