From 3fb80bc9b4e760b7bb2dded9ee4f1d02d7942a0b Mon Sep 17 00:00:00 2001
From: kakkokari-gtyih <67428053+kakkokari-gtyih@users.noreply.github.com>
Date: Tue, 3 Mar 2026 19:05:15 +0900
Subject: [PATCH] =?UTF-8?q?fix:=20OAuth=E3=81=AEContent-Type=E3=82=92?=
 =?UTF-8?q?=E6=AD=A3=E3=81=97=E3=81=8F=E5=88=A4=E5=AE=9A=E3=81=99=E3=82=8B?=
 =?UTF-8?q?=E3=82=88=E3=81=86=E3=81=AB?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 packages/backend/src/server/oauth/OAuth2ProviderService.ts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/backend/src/server/oauth/OAuth2ProviderService.ts b/packages/backend/src/server/oauth/OAuth2ProviderService.ts
index 47f4bf947d..840c34b806 100644
--- a/packages/backend/src/server/oauth/OAuth2ProviderService.ts
+++ b/packages/backend/src/server/oauth/OAuth2ProviderService.ts
@@ -142,7 +142,9 @@ async function discoverClientInformation(logger: Logger, httpRequestService: Htt
 			redirectUris.push(...httpLinkHeader.parse(linkHeader).get('rel', 'redirect_uri').map(r => r.uri));
 		}
 
-		if (res.headers.get('content-type')?.includes('application/json')) {
+		const contentType = res.headers.get('content-type');
+		const mediaType = contentType ? contentType.split(';')[0].trim() : null;
+		if (mediaType === 'application/json') {
 			// Client discovery via JSON document (11 July 2024 spec)
 			// https://indieauth.spec.indieweb.org/#client-metadata
 			// "Clients SHOULD have a JSON [RFC7159] document at their client_id URL containing