Medium severity · published Aug 27, 2026
CVE-2026-81100
Timescale tiger-gh-mcp-server DNS Rebinding via Disabled Host Header Allow-List
6.8
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 12% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
TI
tiger-gh-mcp-server · timescale
before e559b57b57cf61277525ec96bbf1edcf01b16a21 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-81100
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-81100
github.com
https://github.com/timescale/tiger-gh-mcp-server
github.com
https://github.com/timescale/tiger-gh-mcp-server/pull/36
www.vulncheck.com
https://www.vulncheck.com/advisories/timescale-tiger-gh-mcp-server-dns-rebinding-via-disabled-host-header-allow-list
