diff --git a/audio/flac/Makefile b/audio/flac/Makefile
index b3b04c9c9645..7ff50f5804a5 100644
--- a/audio/flac/Makefile
+++ b/audio/flac/Makefile
@@ -1,45 +1,46 @@
 # Created by: Ying-Chieh Liao <ijliao@FreeBSD.org>
 
 PORTNAME=	flac
 PORTVERSION=	1.3.3
+PORTREVISION=	1
 CATEGORIES=	audio
 MASTER_SITES=	https://downloads.xiph.org/releases/flac/
 
 MAINTAINER=	naddy@FreeBSD.org
 COMMENT=	Free lossless audio codec
 
 LICENSE=	BSD3CLAUSE GFDL GPLv2 LGPL21
 LICENSE_COMB=	multi
 LICENSE_FILE_BSD3CLAUSE=${WRKSRC}/COPYING.Xiph
 LICENSE_FILE_GFDL=	${WRKSRC}/COPYING.FDL
 
 LIB_DEPENDS=	libogg.so:audio/libogg
 
 USES=		autoreconf compiler:c11 iconv libtool pathfix pkgconfig tar:xz
 
 USE_LDCONFIG=	yes
 GNU_CONFIGURE=	yes
 CONFIGURE_ARGS=	--enable-static \
 		--disable-sse \
 		--disable-vsx \
 		--with-ogg="${LOCALBASE}" \
 		--disable-doxygen-docs \
 		--disable-thorough-tests \
 		--disable-xmms-plugin
 INSTALL_TARGET=	install-strip
 TEST_TARGET=	check
 
 OPTIONS_DEFINE=	DOCS
 
 .include <bsd.port.options.mk>
 
 .if ${ARCH} == "i386"
 BUILD_DEPENDS+=	nasm:devel/nasm
 .endif
 
 post-install:
 	${REINPLACE_CMD} 's:%%PREFIX%%:${PREFIX}:' \
 	    ${STAGEDIR}${PREFIX}/man/man1/flac.1
 	${RM} ${STAGEDIR}${PREFIX}/man/man1/flac.1.bak
 
 .include <bsd.port.mk>
diff --git a/audio/flac/files/patch-src_libFLAC_bitreader.c b/audio/flac/files/patch-src_libFLAC_bitreader.c
new file mode 100644
index 000000000000..463343e0d428
--- /dev/null
+++ b/audio/flac/files/patch-src_libFLAC_bitreader.c
@@ -0,0 +1,13 @@
+https://github.com/xiph/flac/commit/2e7931c27eb15e387da440a37f12437e35b22dd4
+
+--- src/libFLAC/bitreader.c.orig	2021-05-08 16:06:17 UTC
++++ src/libFLAC/bitreader.c
+@@ -864,7 +864,7 @@ incomplete_lsbs:
+ 			cwords = br->consumed_words;
+ 			words = br->words;
+ 			ucbits = FLAC__BITS_PER_WORD - br->consumed_bits;
+-			b = br->buffer[cwords] << br->consumed_bits;
++			b = cwords < br->capacity ? br->buffer[cwords] << br->consumed_bits : 0;
+ 		} while(cwords >= words && val < end);
+ 	}
+