diff --git a/src/protocol/file/cgi.c b/src/protocol/file/cgi.c
index 5b0e06f8..42e841ea 100644
--- a/src/protocol/file/cgi.c
+++ b/src/protocol/file/cgi.c
@@ -112,12 +112,15 @@ send_post_data(struct connection *conn)
 	unsigned char *post = conn->uri->post;
 	unsigned char *postend;
 	unsigned int files;
+	enum connection_state error;
 
 	postend = strchr(post, '\n');
 	if (postend) post = postend + 1;
-	open_http_post(&http->post, post, &files);
 
-	send_more_post_data(conn->data_socket);
+	if (!open_http_post(&http->post, post, &files, &error))
+		abort_connection(conn, error);
+	else
+		send_more_post_data(conn->data_socket);
 }
 
 static void
diff --git a/src/protocol/http/http.c b/src/protocol/http/http.c
index 9f080a78..e301ad80 100644
--- a/src/protocol/http/http.c
+++ b/src/protocol/http/http.c
@@ -971,6 +971,7 @@ http_send_header(struct socket *socket)
 		 * as set by get_form_uri(). This '\n' is dropped if any
 		 * and replaced by correct '\r\n' termination here. */
 		unsigned char *postend = strchr(uri->post, '\n');
+		enum connection_state error;
 
 		if (postend) {
 			add_to_string(&header, "Content-Type: ");
@@ -979,7 +980,11 @@ http_send_header(struct socket *socket)
 		}
 
 		post_data = postend ? postend + 1 : uri->post;
-		open_http_post(&http->post, post_data, &files);
+		if (!open_http_post(&http->post, post_data, &files, &error)) {
+			http_end_request(conn, error, 0);
+			done_string(&header);
+			return;
+		}
 		add_format_to_string(&header, "Content-Length: "
 				     "%" OFF_PRINT_FORMAT "\x0D\x0A",
 				     (off_print_T)
diff --git a/src/protocol/http/post.c b/src/protocol/http/post.c
index 84fc7dde..c8d6cb8f 100644
--- a/src/protocol/http/post.c
+++ b/src/protocol/http/post.c
@@ -62,6 +62,10 @@ done_http_post(struct http_post *http_post)
  *   pointer remains valid until done_http_post().
  * @param[out] files
  *   The number of files going to be uploaded.
+ * @param[out] error
+ *   If the function fails, it writes the error state here so that
+ *   the caller can pass that on to abort_connection().  If the
+ *   function succeeds, the value of *@a error is undefined.
  *
  * This function does not parse the Content-Type from uri.post; the
  * caller must do that.  This is because in local CGI, the child
@@ -69,10 +73,12 @@ done_http_post(struct http_post *http_post)
  * variable before exec) but the parent process handles the body of
  * the request (feeding it to the child process via a pipe).
  *
+ * @return nonzero on success, zero on error.
+ *
  * @relates http_post */
-void
+int
 open_http_post(struct http_post *http_post, unsigned char *post_data,
-	       unsigned int *files)
+	       unsigned int *files, enum connection_state *error)
 {
 	off_t size = 0;
 	size_t length = strlen(post_data);
@@ -102,6 +108,8 @@ open_http_post(struct http_post *http_post, unsigned char *post_data,
 	}
 	size += (length / 2);
 	http_post->total_upload_length = size;
+
+	return 1;
 }
 
 /** @relates http_post */
diff --git a/src/protocol/http/post.h b/src/protocol/http/post.h
index 562bba30..d0455f82 100644
--- a/src/protocol/http/post.h
+++ b/src/protocol/http/post.h
@@ -4,6 +4,8 @@
 #ifndef EL__PROTOCOL_HTTP_POST_H
 #define EL__PROTOCOL_HTTP_POST_H
 
+#include "network/state.h"
+
 /** State of reading POST data from connection.uri->post and related
  * files.  */
 struct http_post {
@@ -26,9 +28,8 @@ struct http_post {
 
 void init_http_post(struct http_post *http_post);
 void done_http_post(struct http_post *http_post);
-void open_http_post(struct http_post *http_post,
-		    unsigned char *post_data,
-		    unsigned int *files);
+int open_http_post(struct http_post *http_post, unsigned char *post_data,
+		   unsigned int *files, enum connection_state *error);
 int read_http_post(struct http_post *http_post,
 		   unsigned char buffer[], int max);