diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5b68b063..30976a3b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@ Version 254:
 
 * Fix data race in test::stream::connect
 * Fix UB in websocket close tests
+* Fix uninitalized memory use in deflate_stream
 
 --------------------------------------------------------------------------------
 
diff --git a/include/boost/beast/zlib/detail/deflate_stream.ipp b/include/boost/beast/zlib/detail/deflate_stream.ipp
index 4641697c..6532662e 100644
--- a/include/boost/beast/zlib/detail/deflate_stream.ipp
+++ b/include/boost/beast/zlib/detail/deflate_stream.ipp
@@ -623,6 +623,7 @@ init()
 
     window_ = reinterpret_cast<Byte*>(buf_.get());
     prev_   = reinterpret_cast<std::uint16_t*>(buf_.get() + nwindow);
+    std::memset(prev_, 0, nprev);
     head_   = reinterpret_cast<std::uint16_t*>(buf_.get() + nwindow + nprev);
 
     /*  We overlay pending_buf_ and d_buf_ + l_buf_. This works
diff --git a/tools/valgrind.supp b/tools/valgrind.supp
index 1d1ddc0b..7c7c213f 100644
--- a/tools/valgrind.supp
+++ b/tools/valgrind.supp
@@ -3,11 +3,6 @@
    Memcheck:Cond
    fun:fill_window
 }
-{
-   beast_fill_window_no_init
-   Memcheck:Cond
-   fun:_ZN5beast4zlib6detail14deflate_stream11fill_windowIvEEvRNS0_8z_paramsE
-}
 {
    Ignore OpenSSL malloc
    Memcheck:Leak