Vulnerability in Timescale Tiger-Slack
CVE-2026-81099
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.002 (11.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 11th percentile — 11.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.001
Affected products
Weakness classification (CWE)
References
- github.com/timescale/tiger-slack (product)
- github.com/timescale/tiger-slack/pull/146 (issue-tracking, patch)
- www.vulncheck.com/advisories/timescale-tiger-slack-dns-rebinding-via-disabled-h… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-81099?
- CVE-2026-81099 is a medium-severity vulnerability in Timescale Tiger-Slack, classified under Origin Validation Error. CVSS score: 6.8/10. Published 2026-08-27.
- How severe is CVE-2026-81099?
- Medium severity. CVSS v3 base score is 6.8 out of 10.