diff --git a/SOURCES/mozilla-1819244.patch b/SOURCES/mozilla-1819244.patch
new file mode 100644
index 0000000..530284a
--- /dev/null
+++ b/SOURCES/mozilla-1819244.patch
@@ -0,0 +1,23 @@
+diff -up libwebp-0.3.0/src/enc/alpha.c.mozilla-1819244 libwebp-0.3.0/src/enc/alpha.c
+--- libwebp-0.3.0/src/enc/alpha.c.mozilla-1819244	2013-03-29 23:55:16.000000000 +0100
++++ libwebp-0.3.0/src/enc/alpha.c	2023-04-26 12:06:31.017969727 +0200
+@@ -123,8 +123,8 @@ static int EncodeAlphaInternal(const uin
+   header = method | (filter << 2);
+   if (reduce_levels) header |= ALPHA_PREPROCESSED_LEVELS << 4;
+ 
+-  VP8BitWriterInit(bw, expected_size);
+-  VP8BitWriterAppend(bw, &header, ALPHA_HEADER_LEN);
++  ok = VP8BitWriterInit(bw, expected_size);
++  ok = ok && VP8BitWriterAppend(bw, &header, ALPHA_HEADER_LEN);
+ 
+   filter_func = WebPFilters[filter];
+   if (filter_func != NULL) {
+@@ -135,7 +135,7 @@ static int EncodeAlphaInternal(const uin
+   }
+ 
+   if (method == ALPHA_NO_COMPRESSION) {
+-    ok = VP8BitWriterAppend(bw, alpha_src, width * height);
++    ok = ok && VP8BitWriterAppend(bw, alpha_src, width * height);
+     ok = ok && !bw->error_;
+   } else {
+     ok = EncodeLossless(alpha_src, width, height, effort_level, bw, stats);
diff --git a/SPECS/libwebp.spec b/SPECS/libwebp.spec
index 45e8526..26a2500 100644
--- a/SPECS/libwebp.spec
+++ b/SPECS/libwebp.spec
@@ -1,7 +1,7 @@
 %global _hardened_build 1
 Name:		libwebp
 Version:	0.3.0
-Release:	10%{?dist}
+Release:	11%{?dist}
 Group:		Development/Libraries
 URL:		http://webmproject.org/
 Summary:	Library and tools for the WebP graphics format
@@ -14,6 +14,7 @@ Patch1:		libwebp-0.3.0-endian-check2.patch
 Patch2:         rhbz-1956829.patch
 Patch3:         rhbz-1956843.patch
 Patch4:         rhbz-1956919.patch
+Patch5:         mozilla-1819244.patch
 BuildRequires:	libjpeg-devel libpng-devel libtool swig 
 BuildRequires:  giflib-devel
 BuildRequires:  libtiff-devel
@@ -68,6 +69,7 @@ Java bindings for libwebp.
 %patch2 -p1 -b .rhbz-1956829
 %patch3 -p1 -b .rhbz-1956843
 %patch4 -p1 -b .rhbz-1956919
+%patch5 -p1 -b .mozilla-1819244
 
 %build
 mkdir -p m4
@@ -131,6 +133,9 @@ cp swig/*.jar swig/*.so %{buildroot}/%{_libdir}/%{name}-java/
 
 
 %changelog
+* Wed Apr 26 2023 Martin Stransky <stransky@redhat.com> - 0.3.0-11
+- Added fix for mzbz#1819244
+
 * Mon May 17 2021 Martin Stransky <stransky@redhat.com> - 0.3.0-10
 - Added fixes for rhbz#1956829, rhbz#1956843, rhbz#1956919