# CVE-2026-81100

## Summary

- **CVE ID:** CVE-2026-81100
- **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-gh-mcp-server started its MCP HTTP transport without enabling the host allow-list the underlying SDK provides. 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, making the locally reachable GitHub MCP endpoint drivable from a page in a visitor's browser that pointed a name it controlled at the bound address. The fix passes the option explicitly alongside a dependency update; the update alone would not have closed it. The repository has published no release that brackets the fix, so the affected boundary is the commit preceding it.

## Affected Products

- timescale — tiger-gh-mcp-server (e559b57b57cf61277525ec96bbf1edcf01b16a21)
- timescale — tiger-gh-mcp-server (0)

## References

- [CNA](https://github.com/timescale/tiger-gh-mcp-server)
- [CNA](https://github.com/timescale/tiger-gh-mcp-server/pull/36)
- [CNA](https://www.vulncheck.com/advisories/timescale-tiger-gh-mcp-server-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._