diff --git a/CHANGES.rst b/CHANGES.rst
index cfd152544c13c838542524132908dcabe3a27166..0e8e1ef16cf3e82919f3ecbf972062e9bccdf419 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -28,24 +28,59 @@ General
 Node
 ----
 
+- **Breaking change** Enforced stricter validation for the JSON configuration
+  file. Previously, the parser would silently ignore any content that appeared
+  after the first valid JSON object. Now, any extraneous data will cause the
+  function to return an error. (MR :gl:`!18745`)
+
 Client
 ------
 
+- **Breaking change** Enforced stricter validation for the JSON files
+  manipulated by the client. Previously, the parser would silently ignore any
+  content that appeared after the first valid JSON object. Now, any extraneous
+  data will cause the function to return an error. (MR :gl:`!18745`)
+
 Signer
 ------
 
+- **Breaking change** Enforced stricter validation for the JSON files
+  manipulated by the signer. Previously, the parser would silently ignore any
+  content that appeared after the first valid JSON object. Now, any extraneous
+  data will cause the function to return an error. (MR :gl:`!18745`)
+
 Baker
 -----
 
+- **Breaking change** Enforced stricter validation for the JSON files
+  manipulated by the baker. Previously, the parser would silently ignore any
+  content that appeared after the first valid JSON object. Now, any extraneous
+  data will cause the function to return an error. (MR :gl:`!18745`)
+
 Agnostic Baker
 --------------
 
+- **Breaking change** Enforced stricter validation for the JSON files
+  manipulated by the agnostic baker. Previously, the parser would silently
+  ignore any content that appeared after the first valid JSON object. Now, any
+  extraneous data will cause the function to return an error. (MR :gl:`!18745`)
+
 Accuser
 -------
 
+- **Breaking change** Enforced stricter validation for the JSON files
+  manipulated by the accuser. Previously, the parser would silently
+  ignore any content that appeared after the first valid JSON object. Now, any
+  extraneous data will cause the function to return an error. (MR :gl:`!18745`)
+
 Agnostic Accuser
 ----------------
 
+- **Breaking change** Enforced stricter validation for the JSON files
+  manipulated by the agnostic accuser. Previously, the parser would silently
+  ignore any content that appeared after the first valid JSON object. Now, any
+  extraneous data will cause the function to return an error. (MR :gl:`!18745`)
+
 Proxy Server
 ------------
 
@@ -61,6 +96,12 @@ Docker Images
 Smart Rollup node
 -----------------
 
+- **Breaking change** Enforced stricter validation for the JSON configuration
+  file. Previously, the parser would silently ignore any content that appeared
+  after the first valid JSON object. Now, any extraneous data will cause the
+  function to return an error. (MR :gl:`!18745`)
+
+
 Smart Rollup WASM Debugger
 --------------------------
 
@@ -70,5 +111,11 @@ Data Availability Layer (DAL)
 DAL node
 ~~~~~~~~
 
+- **Breaking change** Enforced stricter validation for the JSON configuration
+  file. Previously, the parser would silently ignore any content that appeared
+  after the first valid JSON object. Now, any extraneous data will cause the
+  function to return an error. (MR :gl:`!18745`)
+
+
 Miscellaneous
 -------------
diff --git a/etherlink/CHANGES_NODE.md b/etherlink/CHANGES_NODE.md
index 4a87863f766cae19bb0f00c01e6a67290e435641..d71c16d0298785fdb91c96ec9d465fdb1c0e6477 100644
--- a/etherlink/CHANGES_NODE.md
+++ b/etherlink/CHANGES_NODE.md
@@ -16,6 +16,11 @@
 
 ### Execution changes
 
+- Enforces stricter validation for the JSON configuration file. Previously,
+  the parser would silently ignore any content that appeared after the first
+  valid JSON object. Now, any extraneous data will cause the function to return
+  an error. (!18745)
+
 ### Storage changes
 
 ### Documentation changes
diff --git a/src/lib_stdlib_unix/lwt_utils_unix.ml b/src/lib_stdlib_unix/lwt_utils_unix.ml
index a729fd84d318e9e7e1aad4a42bf4f3094ecd2431..01bac84d833162740df2036a36eec618d8125ec0 100644
--- a/src/lib_stdlib_unix/lwt_utils_unix.ml
+++ b/src/lib_stdlib_unix/lwt_utils_unix.ml
@@ -302,6 +302,19 @@ let getpass () =
   passwd
 
 module Json = struct
+  type error += Json_decoding_error of {input : string; error : string}
+
+  let () =
+    register_error_kind
+      `Temporary
+      ~id:"json_decoding_error"
+      ~title:"Json decoding error"
+      ~description:"The input string is not a valid JSON value"
+      Data_encoding.(obj2 (req "input" string) (req "error" string))
+      (function
+        | Json_decoding_error {input; error} -> Some (input, error) | _ -> None)
+      (fun (input, error) -> Json_decoding_error {input; error})
+
   let to_root = function
     | `O ctns -> `O ctns
     | `A ctns -> `A ctns
@@ -322,7 +335,9 @@ module Json = struct
         Lwt_io.with_file ~mode:Input file (fun chan ->
             let open Lwt_result_syntax in
             let*! str = Lwt_io.read chan in
-            return (Ezjsonm.from_string str :> Data_encoding.json)))
+            match Data_encoding.Json.from_string str with
+            | Ok json -> return json
+            | Error error -> tzfail (Json_decoding_error {input = str; error})))
 end
 
 (* This module is used by [safe_cancel_on_exit] to register and unregister