help request: "400 Request Header Or Cookie Too Large"

[anmoln4]

Description

Users encounter 400 Bad Request: Request Header Or Cookie Too Large.

logs:

2025/07/16 10:59:15 [info] 53#53: *2841 client sent too long header line: "key: value.."

Config.yaml:
`nginx_config: # config for render the template to genarate nginx.conf
error_log: "/dev/stderr"
error_log_level: "info" # warn,error
worker_processes: "auto"
enable_cpu_affinity: true
worker_rlimit_nofile: 20480 # the number of files a worker process can open, should be larger than worker_connections
event:
worker_connections: 10620
meta:
lua_shared_dict:
prometheus-metrics: 15m

http:

enable_access_log: true
access_log: "/dev/stdout"
access_log_format: '$remote_addr - $remote_user [$time_local] $http_host \"$request\" $status $body_bytes_sent $request_time \"$http_referer\" \"$http_user_agent\" $upstream_addr $upstream_status $upstream_response_time \"$upstream_scheme://$upstream_host$upstream_uri\"'
access_log_format_escape: default
keepalive_timeout: 60s         # timeout during which a keep-alive client connection will stay open on the server side.

client_body_timeout: 60s       # timeout for reading client request body, then 408 (Request Time-out) error is returned to the client
send_timeout: 10s              # timeout for transmitting a response to the client.then the connection is closed
underscores_in_headers: "on"   # default enables the use of underscores in client request header fields
real_ip_header: "X-Real-IP"    # http://nginx.org/en/docs/http/ngx_http_realip_module.html#real_ip_header
real_ip_from:                  # http://nginx.org/en/docs/http/ngx_http_realip_module.html#set_real_ip_from
  - 127.0.0.1
  - 'unix:'

client_header_buffer_size: 1m       # 1MB initial buffer
large_client_header_buffers: 4 2m   # 8MB total header buffer (4 buffers × 2MB)

Environment

• APISIX version (run apisix version): 3.8.0
• Operating system (run uname -a): Linux
• OpenResty / Nginx version (run openresty -V or nginx -V): openresty/1.21.4.2`

[Baoyuantop]

You cannot add these configuration items directly under nginx_config.http, you should use http_configuration_snippet to add custom nginx configuration.

[anmoln4]

Hi @Baoyuantop , we tried the same client header settings in http_configuration_snippet in apisix configmap. But still we are getting same error.

[Baoyuantop]

Could you provide your configuration information and steps to reproduce the issue?

[anmoln4]

`apisix: # universal configurations
node_listen: # APISIX listening port
- 9080
enable_heartbeat: true
enable_admin: false

enable_admin_cors: true
enable_debug: false

enable_dev_mode: false # Sets nginx worker_processes to 1 if set to true
enable_reuseport: true # Enable nginx SO_REUSEPORT switch if set to true.
enable_ipv6: true # Enable nginx IPv6 resolver
enable_server_tokens: true # Whether the APISIX version number should be shown in Server header

proxy_cache: # Proxy Caching configuration
cache_ttl: 10s # The default caching time if the upstream does not specify the cache time
zones: # The parameters of a cache
- name: disk_cache_one # The name of the cache, administrator can be specify
# which cache to use by name in the admin api
memory_size: 50m # The size of shared memory, it's used to store the cache index
disk_size: 1G # The size of disk, it's used to store the cache data
disk_path: "/tmp/disk_cache_one" # The path to store the cache data
cache_levels: "1:2" # The hierarchy levels of a cache

- name: disk_cache_two

memory_size: 50m

disk_size: 1G

disk_path: "/tmp/disk_cache_two"

cache_levels: "1:2"

router:
http: radixtree_host_uri # radixtree_uri: match route by uri(base on radixtree)
# radixtree_host_uri: match route by host + uri(base on radixtree)
# radixtree_uri_with_parameter: match route by uri with parameters
ssl: 'radixtree_sni' # radixtree_sni: match route by SNI(base on radixtree)

proxy_mode: http
dns_resolver_valid: 30
resolver_timeout: 5
ssl:
enable: false
listen:
- port: 9443
enable_http2: true
ssl_protocols: "TLSv1.2 TLSv1.3"
ssl_ciphers: "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES256-SHA256:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA"

nginx_config: # config for render the template to genarate nginx.conf
error_log: "/dev/stderr"
error_log_level: "info" # warn,error
worker_processes: "auto"
enable_cpu_affinity: true
worker_rlimit_nofile: 20480 # the number of files a worker process can open, should be larger than worker_connections
event:
worker_connections: 10620
meta:
lua_shared_dict:
prometheus-metrics: 15m

http:
enable_access_log: true
access_log: "/dev/stdout"
access_log_format: '$remote_addr - $remote_user [$time_local] $http_host "$request" $status $body_bytes_sent $request_time "$http_referer" "$http_user_agent" $upstream_addr $upstream_status $upstream_response_time "$upstream_scheme://$upstream_host$upstream_uri"'
access_log_format_escape: default
keepalive_timeout: 60s # timeout during which a keep-alive client connection will stay open on the server side.
client_header_timeout: 60s # timeout for reading client request header, then 408 (Request Time-out) error is returned to the client
client_body_timeout: 60s # timeout for reading client request body, then 408 (Request Time-out) error is returned to the client
send_timeout: 10s # timeout for transmitting a response to the client.then the connection is closed
underscores_in_headers: "on" # default enables the use of underscores in client request header fields
real_ip_header: "X-Real-IP" # http://nginx.org/en/docs/http/ngx_http_realip_module.html#real_ip_header
real_ip_from: # http://nginx.org/en/docs/http/ngx_http_realip_module.html#set_real_ip_from
- 127.0.0.1
- 'unix:'
http_configuration_snippet: |
proxy_buffer_size 16k;
client_header_buffer_size: 1m # 1MB initial buffer
large_client_header_buffers: 4 2m
http_server_configuration_snippet: |
proxy_buffer_size 16k;
discovery:
kubernetes: {}

deployment:
role: data_plane
role_data_plane:
config_provider: yaml`

The above configuration we tried but getting same error: 400 client sent too long header

:

Issue: when we are sending jwt of more than 8kb , then we are getting this issue.