{"id":"CVE-2026-81099","title":"tiger-slack started its MCP HTTP transport without enabling the host allow-list the underlying SDK provides","summary":"tiger-slack started its MCP HTTP transport without enabling the host allow-list the underlying SDK provides. mcp/src/httpServer.ts called the shared httpServerFactory helper and never set the DNS-rebinding-protection option, so the trans…","severity":"medium","cvss":6.8,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N","cwe":["CWE-346"],"published":"2026-08-27","updated":"2026-09-23","sourceUpdated":"2026-09-23T17:17:42.577","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-81099","references":[{"url":"https://github.com/timescale/tiger-slack","label":"disclosure@vulncheck.com"},{"url":"https://github.com/timescale/tiger-slack/pull/146","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/timescale-tiger-slack-dns-rebinding-via-disabled-host-header-allow-list","label":"disclosure@vulncheck.com"}],"tags":["nvd"],"epss":0.0016,"epssPercentile":0.05619,"ingestedAt":"2026-09-23T17:28:14.807Z","slug":"CVE-2026-81099","body":"## Overview\n\ntiger-slack started its MCP HTTP transport without enabling the host allow-list the underlying SDK provides. mcp/src/httpServer.ts called the shared httpServerFactory helper and never set the DNS-rebinding-protection option, so the transport accepted a request whatever host it named, and a page in a browser could point a name it controlled at the address the server was bound to and drive the locally reachable Slack MCP server through the visitor's browser. The fix passes the option explicitly alongside a dependency update; the update alone would not have closed it. The repository publishes no release that brackets the fix, so the affected boundary is the commit preceding it.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":37,"depthScoreParts":{"impact":37.4,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}