CVE-2026-81100

Severity CVSS v4.0:

HIGH

Type:

Unavailable / Other

Publication date:

27/08/2026

Last modified:

27/08/2026

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&#39;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.

Impact

Vector 4.0

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 CVSS v4.0 Severity and Metrics:

Base Score: 7.60 HIGH
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

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): Present
Privileges Required (PR): None
User Interaction (UI): Passsive
Confidentiality (VC): High
Integrity (VI): High
Availability (VA): None
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): None

Base Score 4.0

7.60

Severity 4.0

HIGH

Vector 3.x

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N CVSS v3.1 Severity and Metrics:

Base Score: 6.80 MEDIUM
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): Required
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): None

Base Score 3.x

6.80

Severity 3.x

MEDIUM

CVE-2026-81100

Description

Impact

References to Advisories, Solutions, and Tools