{"cve":"CVE-2026-27826","nvd":{"published":"2026-03-10T19:17:20.670","modified":"2026-06-17T10:27:44.990","status":"Analyzed","description":"MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to version 0.17.0, an unauthenticated attacker who can reach the mcp-atlassian HTTP endpoint can force the server process to make outbound HTTP requests to an arbitrary attacker-controlled URL by supplying two custom HTTP headers without an `Authorization` header. No authentication is required. The vulnerability exists in the HTTP middleware and dependency injection layer — not in any MCP tool handler - making it invisible to tool-level code analysis. In cloud deployments, this could enable theft of IAM role credentials via the instance metadata endpoint (`169[.]254[.]169[.]254`). In any HTTP deployment it enables internal network reconnaissance and injection of attacker-controlled content into LLM tool results. Version 0.17.0 fixes the issue.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N","score":8.2},"cwes":["CWE-918"],"references":["https://github.com/sooperset/mcp-atlassian/commit/5cd697dfce9116ef330b8dc7a91291640e0528d9","https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-7r34-79r5-rcc9"],"products":["sooperset:mcp_atlassian"],"source":"nvd","synced_at":"2026-10-19T22:25:53.701907451+00:00"},"epss":{"cve":"CVE-2026-27826","score":0.13,"percentile":0.96331,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-7r34-79r5-rcc9","url":"https://osv.dev/vulnerability/GHSA-7r34-79r5-rcc9","summary":"MCP Atlassian has SSRF via unvalidated X-Atlassian-Jira-Url / X-Atlassian-Confluence-Url headers","modified":"2026-07-13T16:43:48.991534647Z","packages":[{"ecosystem":"PyPI","name":"mcp-atlassian","purl":"pkg:pypi/mcp-atlassian","ranges":["<0.17.0"],"fixed":["0.17.0"]}]},{"id":"PYSEC-2026-2621","url":"https://osv.dev/vulnerability/PYSEC-2026-2621","summary":"MCP Atlassian has SSRF via unvalidated X-Atlassian-Jira-Url / X-Atlassian-Confluence-Url headers","modified":"2026-07-13T16:32:12.528827078Z","packages":[{"ecosystem":"PyPI","name":"mcp-atlassian","purl":"pkg:pypi/mcp-atlassian","ranges":["<0.17.0"],"fixed":["0.17.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}