diff --git a/config.sh b/config.sh
index ddcf152a8..9ac546bf0 100644
--- a/config.sh
+++ b/config.sh
@@ -4,7 +4,7 @@
 # Package versions for fresh source builds
 FREETYPE_VERSION=2.6.5
 LIBPNG_VERSION=1.6.25
-ZLIB_VERSION=1.2.8
+ZLIB_VERSION=1.2.9
 JPEG_VERSION=9b
 OPENJPEG_VERSION=2.1
 TIFF_VERSION=4.0.6