SSRF (Server-Side Request Forgery) in github.com/modelcontextprotocol/registry (CVE-2026-44428)
Summary
SSRF in github.com/modelcontextprotocol/registry (CVE-2026-44428). Risk of unauthorized operations or information disclosure. Exploitable via c5c4b9e8890dd5754bee889b2f1417f4fe3b5ce5. Mitigation: upgrade to 1.7.6 or later.
Original description
The description as published by the source.
[SECURITY] registry_001 Vulnerability Report
While analyzing the code logic, an area that may lead to unintended behavior under specific conditions was discovered.
Overview
- Verified Version:
c5c4b9e8890dd5754bee889b2f1417f4fe3b5ce5 - Vulnerability Type: Authentication bypass via cross-registry OIDC token replay
- Affected Location:
cmd/publisher/commands/login.go:67-105,130-135,199-224;cmd/publisher/auth/github-oidc.go:24-38,58-75,108-165;internal/api/handlers/v0/auth/github_oidc.go:75-135,229-277,280-296 - Trigger Scenario: a workflow invokes
mcp-publisher login github-oidc --registry(or equivalent publish flow) and the publisher still requests a GitHub Actions ID token with the shared audiencemcp-registry; any other registry deployment running this code can replay that token to its own/v0/auth/github-oidcendpoint and mint a publish-capable registry JWT for the same GitHub owner namespace.
Root Cause
The client-side and server-side GitHub OIDC flow is bound only to a global audience string, not to the specific registry instance being targeted. On the client side, the publisher always appends audience=mcp-registry when requesting the GitHub Actions ID token, regardless of the selected --registry URL. On the server side, the exchange endpoint validates only that same fixed audience and then derives publish permissions directly from repository_owner. As a result, a token legitimately obtained while interacting with one registry deploymen…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-44428 has been found in github.com/modelcontextprotocol/registry.
Attackers can target a specific entry point like c5c4b9e8890dd5754bee889b2f1417f4fe3b5ce5 over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 4.7/10.
What to do: upgrade github.com/modelcontextprotocol/registry to 1.7.6 or later.
If unsure, ask your IT team or search "github.com/modelcontextprotocol/registry CVE-2026-44428" on the vendor's site.
CVE-2026-44428 (github.com/modelcontextprotocol/registry) — CWE-918 / CVSS v3 4.7
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: c5c4b9e8890dd5754bee889b2f1417f4fe3b5ce5 / repository_owner / flags.RegistryURL / GitHubOIDCProvider
Patched: 1.7.6 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
SSRF (CWE-918) exists in github.com/modelcontextprotocol/registry. Attackers reach the vulnerable code path via c5c4b9e8890dd5754bee889b2f1417f4fe3b5ce5 without authentication.
Check the vendor advisory for the affected versions of github.com/modelcontextprotocol/registry. Attack surface: c5c4b9e8890dd5754bee889b2f1417f4fe3b5ce5 / repository_owner / flags.RegistryURL / GitHubOIDCProvider.
Severity: Medium (CVSS 4.7/10). Risk of unauthorized operations or information disclosure.
Update to 1.7.6.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/modelcontextprotocol/registry' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/modelcontextprotocol/registry' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/modelcontextprotocol/registryを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade github.com/modelcontextprotocol/registry to 1.7.6ステージング環境で 1.7.6 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com