# CVE-2026-81099

## Summary

- **CVE ID:** CVE-2026-81099
- **Severity:** HIGH
- **CVSS Score:** 7.6 (CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N)
- **CWE:** CWE-346
- **Published:** Aug 27, 2026
- **Last Modified:** Aug 29, 2026

## Description

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 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.

## Affected Products

- timescale — tiger-slack (23faf7ee7e7f73e5ea4f67e627c1aca94bba1f09)
- timescale — tiger-slack (0)

## References

- [CNA](https://github.com/timescale/tiger-slack)
- [CNA](https://github.com/timescale/tiger-slack/pull/146)
- [CNA](https://www.vulncheck.com/advisories/timescale-tiger-slack-dns-rebinding-via-disabled-host-header-allow-list)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.16%
- **EPSS Percentile:** 5.5

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._