How severe is GHSA-v8vw-gw5j-w7m6?

No CVSS score has been assigned to GHSA-v8vw-gw5j-w7m6 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-v8vw-gw5j-w7m6?

GHSA-v8vw-gw5j-w7m6 affects the following packages: github.com/modelcontextprotocol/registry (Go). Ecosystems affected: Go.

How do I fix GHSA-v8vw-gw5j-w7m6?

Update github.com/modelcontextprotocol/registry to 1.7.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v8vw-gw5j-w7m6 is resolved across your whole dependency graph.

How do I detect GHSA-v8vw-gw5j-w7m6 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/modelcontextprotocol/registry. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-v8vw-gw5j-w7m6 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-v8vw-gw5j-w7m6?

O3 pinpoints whether GHSA-v8vw-gw5j-w7m6 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-v8vw-gw5j-w7m6 actively exploited in the wild?

No public exploit code has been indexed for GHSA-v8vw-gw5j-w7m6 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-v8vw-gw5j-w7m6 published, and has it been updated?

GHSA-v8vw-gw5j-w7m6 was published on May 8, 2026 and was last updated on June 25, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

GHSA-v8vw-gw5j-w7m6

Fix: modelcontextprotocol/registry#1227

GHSA-v8vw-gw5j-w7m6 is a security vulnerability in github.com/modelcontextprotocol/registry. O3 Security confirms whether GHSA-v8vw-gw5j-w7m6 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

MCP Registry has open redirect via protocol-relative path in trailing-slash middleware

Also known asCVE-2026-44427GO-2026-5658

Published

May 8, 2026

Updated

Jun 25, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Real-World Exposure

1 pkg affected

🐹github.com/modelcontextprotocol/registry

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Summary

The TrailingSlashMiddleware in internal/api/server.go is vulnerable to an open redirect attack. An attacker can craft a URL with a protocol-relative path (e.g., //evil.com/) that, after trailing slash removal, results in a Location header of //evil.com — which browsers interpret as an absolute URL to an external domain.

Details

The TrailingSlashMiddleware strips trailing slashes from request paths and issues a 308 Permanent Redirect to the cleaned path. However, it does not validate or sanitize the resulting path before using it as the redirect target.

When a request is made with a path like //evil.com/, the middleware processes it as follows:

PoC

Start the registry server locally or identify a deployed instance
Send a request with a double-slash path followed by an external domain: curl -v https://<registry-host>//evil.com/ <img width="3066" height="969" alt="image" src="https://github.com/user-attachments/assets/a5305f00-29bf-4708-952a-478d608f2074" />
Observe the 308 Permanent Redirect response with Location: //evil.com:
When accessed in a browser, the user is redirected to https://evil.com

Impact

Phishing: Attackers can abuse the trusted registry domain to redirect users to credential-harvesting pages Malware distribution: Redirect users to sites serving malicious downloads Trust abuse: Links originating from the official MCP Registry domain carry implicit trust

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/modelcontextprotocol/registry`	≥ 1.1.0&&< 1.7.5	1.7.5

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/modelcontextprotocol/registry. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/modelcontextprotocol/registry to 1.7.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v8vw-gw5j-w7m6 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-v8vw-gw5j-w7m6 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-v8vw-gw5j-w7m6. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary The TrailingSlashMiddleware in internal/api/server.go is vulnerable to an open redirect attack. An attacker can craft a URL with a protocol-relative path (e.g., //evil.com/) that, after trailing slash removal, results in a Location header of //evil.com — which browsers interpret as an absolute URL to an external domain. ### Details The TrailingSlashMiddleware strips trailing slashes from request paths and issues a 308 Permanent Redirect to the cleaned path. However, it does not validate or sanitize the resulting path before using it as the redirect target. When a request is made

O3 Security · Impact-Aware SCA

Is GHSA-v8vw-gw5j-w7m6 in your dependencies?

O3 detects GHSA-v8vw-gw5j-w7m6 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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