diff --git a/changelog.md b/changelog.md
index 33fc397b6..e5224a0c2 100644
--- a/changelog.md
+++ b/changelog.md
@@ -11,6 +11,7 @@
 * `FIX` Typed `@field` (eg `---@field [string] boolean`) should not override other defined field [#2171](https://github.com/LuaLS/lua-language-server/issues/2171), [#2711](https://github.com/LuaLS/lua-language-server/issues/2711)
 * `FIX` don't return empty hover doc when luals failed to find definition
 * `FIX` Prevent stack overflow when attempting to resolve function return values. [#3246](https://github.com/LuaLS/lua-language-server/issues/3246)
+* `FIX` Fix type annotations for `string.buffer` module
 
 ## 3.15.0
 `2025-6-25`
diff --git a/meta/template/string.buffer.lua b/meta/template/string.buffer.lua
index 7285290a4..950e70262 100644
--- a/meta/template/string.buffer.lua
+++ b/meta/template/string.buffer.lua
@@ -262,7 +262,7 @@ function buf:ref() end
 --- Serializes (encodes) the Lua object to the buffer
 ---
 --- This function may throw an error when attempting to serialize unsupported object types, circular references or deeply nested tables.
----@param obj string.buffer.data
+---@param obj any
 ---@return string.buffer
 function buf:encode(obj) end
 
@@ -277,14 +277,14 @@ function buf:encode(obj) end
 ---
 --- Attempting to de-serialize an FFI type will throw an error, if the FFI library is not built-in or has not been loaded, yet.
 ---
----@return string.buffer.data|nil obj
+---@return any obj
 function buf:decode() end
 
 
 --- Serializes (encodes) the Lua object obj
 ---
 --- This function may throw an error when attempting to serialize unsupported object types, circular references or deeply nested tables.
----@param obj string.buffer.data
+---@param obj any
 ---@return string
 function buffer.encode(obj) end
 
@@ -298,7 +298,7 @@ function buffer.encode(obj) end
 --- Attempting to de-serialize an FFI type will throw an error, if the FFI library is not built-in or has not been loaded, yet.
 ---
 ---@param str string
----@return string.buffer.data|nil obj
+---@return any obj
 function buffer.decode(str) end