From: Marek Ludha <marek.ludha@eset.com>
Date: Fri, 25 Sep 2026 13:19:04 +0000 (+0200)
Subject: HTTP/2: ignore unknown flags in the SETTINGS message
X-Git-Url: https://git.kaiwu.me/?a=commitdiff_plain;h=cc1bbc7f7e32195928f89d9a652b38fe9c975c8e;p=nginx.git

HTTP/2: ignore unknown flags in the SETTINGS message

This is required by RFC9113 section 4.1:
"Unused flags MUST be ignored on receipt"
---

diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c
index 35683ab75..b4297e929 100644
--- a/src/http/v2/ngx_http_v2.c
+++ b/src/http/v2/ngx_http_v2.c
@@ -2222,7 +2222,7 @@ ngx_http_v2_state_settings(ngx_http_v2_connection_t *h2c, u_char *pos,
         return ngx_http_v2_connection_error(h2c, NGX_HTTP_V2_PROTOCOL_ERROR);
     }
 
-    if (h2c->state.flags == NGX_HTTP_V2_ACK_FLAG) {
+    if (h2c->state.flags & NGX_HTTP_V2_ACK_FLAG) {
 
         if (h2c->state.length != 0) {
             ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0,