new file mode 100644
@@ -0,0 +1,129 @@
+From ee81b4f4b2f8e7d1a49c92d8a470294ef7088045 Mon Sep 17 00:00:00 2001
+From: Daniel Stenberg <daniel@haxx.se>
+Date: Tue, 14 Apr 2026 08:51:44 +0200
+Subject: [PATCH] urldata: move cookiehost to struct SingleRequest
+
+To make it scoped for the single request appropriately.
+
+Reported-by: Muhamad Arga Reksapati
+
+Verify with libtest 2504: a custom Host *disabled* on reused handle
+
+Closes #21312
+
+CVE: CVE-2026-6276
+Upstream-Status: Backport [https://github.com/curl/curl/commit/3a19987a87f393d9394fe5acc7643f6c263c92db]
+
+Signed-off-by: Adarsh Jagadish Kamini <adarsh.jagadish.kamini@est.tech>
+---
+ lib/http.c | 16 ++++++++++------
+ lib/request.c | 3 +++
+ lib/request.h | 3 +++
+ lib/url.c | 4 +++-
+ lib/urldata.h | 1 -
+ 5 files changed, 19 insertions(+), 8 deletions(-)
+
+diff --git a/lib/http.c b/lib/http.c
+index b80bebf..b1f6040 100644
+--- a/lib/http.c
++++ b/lib/http.c
+@@ -1747,7 +1747,11 @@ CURLcode Curl_http_host(struct Curl_easy *data, struct connectdata *conn)
+ data->state.first_remote_port = conn->remote_port;
+ data->state.first_remote_protocol = conn->handler->protocol;
+ }
++
+ Curl_safefree(aptr->host);
++#ifndef CURL_DISABLE_COOKIES
++ Curl_safefree(data->req.cookiehost);
++#endif
+
+ ptr = Curl_checkheaders(data, STRCONST("Host"));
+ if(ptr && (!data->state.this_is_a_follow ||
+@@ -1782,8 +1786,8 @@ CURLcode Curl_http_host(struct Curl_easy *data, struct connectdata *conn)
+ if(colon)
+ *colon = 0; /* The host must not include an embedded port number */
+ }
+- Curl_safefree(aptr->cookiehost);
+- aptr->cookiehost = cookiehost;
++ Curl_safefree(data->req.cookiehost);
++ data->req.cookiehost = cookiehost;
+ }
+ #endif
+
+@@ -2302,8 +2306,8 @@ CURLcode Curl_http_cookies(struct Curl_easy *data,
+ int count = 0;
+
+ if(data->cookies && data->state.cookie_engine) {
+- const char *host = data->state.aptr.cookiehost ?
+- data->state.aptr.cookiehost : conn->host.name;
++ const char *host = data->req.cookiehost ?
++ data->req.cookiehost : conn->host.name;
+ const bool secure_context =
+ conn->handler->protocol&(CURLPROTO_HTTPS|CURLPROTO_WSS) ||
+ strcasecompare("localhost", host) ||
+@@ -3121,8 +3125,8 @@ CURLcode Curl_http_header(struct Curl_easy *data, struct connectdata *conn,
+ if(v) {
+ /* If there is a custom-set Host: name, use it here, or else use
+ * real peer host name. */
+- const char *host = data->state.aptr.cookiehost?
+- data->state.aptr.cookiehost:conn->host.name;
++ const char *host = data->req.cookiehost?
++ data->req.cookiehost:conn->host.name;
+ const bool secure_context =
+ conn->handler->protocol&(CURLPROTO_HTTPS|CURLPROTO_WSS) ||
+ strcasecompare("localhost", host) ||
+diff --git a/lib/request.c b/lib/request.c
+index b3b0582..9bede2e 100644
+--- a/lib/request.c
++++ b/lib/request.c
+@@ -111,6 +111,9 @@ void Curl_req_hard_reset(struct SingleRequest *req, struct Curl_easy *data)
+ * free this safely without leaks. */
+ Curl_safefree(req->p.http);
+ Curl_safefree(req->newurl);
++#ifndef CURL_DISABLE_COOKIES
++ Curl_safefree(req->cookiehost);
++#endif
+ Curl_client_reset(data);
+ if(req->sendbuf_init)
+ Curl_bufq_reset(&req->sendbuf);
+diff --git a/lib/request.h b/lib/request.h
+index 488fbdd..17d50a3 100644
+--- a/lib/request.h
++++ b/lib/request.h
+@@ -118,6 +118,9 @@ struct SingleRequest {
+ #ifndef CURL_DISABLE_DOH
+ struct dohdata *doh; /* DoH specific data for this request */
+ #endif
++#ifndef CURL_DISABLE_COOKIES
++ char *cookiehost;
++#endif
+ #ifndef CURL_DISABLE_COOKIES
+ unsigned char setcookies;
+ #endif
+diff --git a/lib/url.c b/lib/url.c
+index 76360c8..30f215f 100644
+--- a/lib/url.c
++++ b/lib/url.c
+@@ -313,7 +313,9 @@ CURLcode Curl_close(struct Curl_easy **datap)
+ Curl_safefree(data->state.aptr.rangeline);
+ Curl_safefree(data->state.aptr.ref);
+ Curl_safefree(data->state.aptr.host);
+- Curl_safefree(data->state.aptr.cookiehost);
++#ifndef CURL_DISABLE_COOKIES
++ Curl_safefree(data->req.cookiehost);
++#endif
+ Curl_safefree(data->state.aptr.rtsp_transport);
+ Curl_safefree(data->state.aptr.user);
+ Curl_safefree(data->state.aptr.passwd);
+diff --git a/lib/urldata.h b/lib/urldata.h
+index b68d023..4fc595a 100644
+--- a/lib/urldata.h
++++ b/lib/urldata.h
+@@ -1339,7 +1339,6 @@ struct UrlState {
+ char *rangeline;
+ char *ref;
+ char *host;
+- char *cookiehost;
+ char *rtsp_transport;
+ char *te; /* TE: request header */
+
@@ -36,6 +36,7 @@ SRC_URI = " \
file://CVE-2026-1965-2.patch \
file://CVE-2026-3783.patch \
file://CVE-2026-3784.patch \
+ file://CVE-2026-6276.patch \
"
SRC_URI:append:class-nativesdk = " \