@zereight/mcp-gitlab: DNS rebinding reaches local Streamable HTTP MCP transport

published 2026-09-15 54 d ago modified 2026-09-30 39 d ago also GHSA-vmp7-252j-cwp7 , EUVD-2026-79999

cvss: 9.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits: 0; none known

`@zereight/mcp-gitlab` is a Model Context Protocol server for GitLab. Versions prior to 2.1.30 expose the Streamable HTTP MCP endpoint without an effective Host or Origin allowlist. A malicious web page can use DNS rebinding to route browser requests to a victim's local MCP listener while preserving an attacker-controlled `Host` and `Origin`. The server accepts those headers and reaches the MCP initialization path instead of rejecting the request at the HTTP boundary. Version 2.1.30 contains a patch.

Patch / fix

fixed in 1 links 3

npm @zereight/mcp-gitlab 2.1.30

github.com/zereight/gitlab-mcp@52207c6 commit
github.com/zereight/gitlab-mcp#555 pull request
github.com/zereight/gitlab-mcp/releases/tag/v2.1.30 release

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 53 d ago (2026-09-16)

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
GitHub	3.1	9.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
npm	@zereight/mcp-gitlab	<2.1.30	2.1.30

Affected products

zereight gitlab-mcp

Classification

Weakness

CWE-350 Reliance on Reverse DNS Resolution for a Security-Critical Action

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary