GHSA-4pc9-x2fx-p7vj · 深刻度： medium · エコシステム： npm — @cloudflare/workers-oauth-provider missing validation of redirect_uri on authorize endpoint
The OAuth implementation in workers-oauth-provider that is part of MCP framework https://github.com/cloudflare/workers-mcp , did not correctly validate that redirect_uri was on the allowed list of redirect URIs for the given client registration. Fixed in: https://github.com/cloudflare/workers-oauth-provider/pull/26 https://github.com/cloudflare/workers-oauth-provider/pull/26 Impact: Under certain circumstances (see below), if a victim had previously authorized with a server built on workers-oath-provider, and an attacker could later trick the victim into visiting a malicious web site, then attacker could potentially steal the victim's credentials to the same OAuth server and subsequently impersonate them. In order for the attack to be possible, the OAuth server's authorized callback must be designed to auto-approve authorizations that appear to come from an OAuth client that the victim has authorized previously. The authorization flow is not implemented by workers-oauth-provider; it is up to the application built on top to decide whether to implement such automatic re-authorization. However, many applications do implement such logic. Note: It is a basic, well-known requirement that OAuth servers should verify that the redirect URI is among the allowed list for the client, both during the authorization flow and subsequently when exchanging the authorization code for an access token. workers-oauth-provider implemented only the latter check, not the former. Unfortunately, the former is the much more important check. Readers who are familiar with OAuth may recognize that failing to check redirect URIs against the allowed list is a well-known, basic mistake, covered extensively in the RFC and elsewhere. The author of this library would like everyone to know that he was, in fact, well-aware of this requirement, thought about it a lot while designing the library, and then, somehow, forgot to actually make sure the check was in the code. That is, it's not that he didn't know what he was doing, it's that he knew what he was doing but flubbed it.
総合評価: CVE-2025-4143 は中リスク（42.1/100）。CVSS 深刻度は中。悪用される可能性が高い（EPSS 0.28%、51 パーセンタイル） 推奨対応: 影響資産を整理し、修補計画に組み込んでください。
リスクは変動します。再評価に基づき、本ページの表示内容を更新しています。
EPSS は日次で悪用されやすさの相対度合いを推定します。パーセンタイルは採点済み CVE の中での相対位置（高いほど相対的に深刻）を示します。
| # | 日付 | 旧 EPSS スコア | 新 EPSS スコア | Δ（新 − 旧） |
|---|---|---|---|---|
| 1 | 2026-06-09 | 0.14% | 0.28% | +0.14% |
| 2 | 2026-05-29 | 0.25% | 0.14% | -0.12% |
| 3 | 2026-04-30 | — | 0.25% | — |
EPSS の全履歴 （全 17 件）
この CVE の CVSS 指標。
| ベーススコア | バージョン | 深刻度 | ベクトル | 悪用しやすさ | 影響 | スコアの出典 |
|---|---|---|---|---|---|---|
| 6.0 | 4.0 | MEDIUM |
|
— | — | [email protected] |
| 6.1 | 3.1 | MEDIUM |
|
2.8 | 2.7 | [email protected] |
GHSA-4pc9-x2fx-p7vj · 深刻度： medium · エコシステム： npm — @cloudflare/workers-oauth-provider missing validation of redirect_uri on authorize endpoint
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| cloudflare | workers-oauth-provider | 0.0.5 | cpe:2.3:a:cloudflare:workers-oauth-provider:0.0.5:*:*:*:*:*:*:* |
| URL | タグ |
|---|---|
| https://github.com/cloudflare/workers-oauth-provider/pull/26 | Issue Tracking Patch |