diff --git a/astro/cfitsio/Makefile b/astro/cfitsio/Makefile
index e895d8ff012f..d02fbe4d00d9 100644
--- a/astro/cfitsio/Makefile
+++ b/astro/cfitsio/Makefile
@@ -1,37 +1,37 @@
 PORTNAME=	cfitsio
-PORTVERSION=	4.6.3
+PORTVERSION=	4.6.4
 CATEGORIES=	astro
 MASTER_SITES=	https://heasarc.gsfc.nasa.gov/FTP/software/fitsio/c/ \
 		https://heasarc.gsfc.nasa.gov/FTP/software/fitsio/c/oldvers/ \
 		LOCAL/sunpoet
 
 MAINTAINER=	sunpoet@FreeBSD.org
 COMMENT=	Library for reading and writing files in FITS data format
 WWW=		https://heasarc.gsfc.nasa.gov/fitsio/ \
 		https://github.com/HEASARC/cfitsio
 
 LICENSE=	CFITSIO
 LICENSE_NAME=	CFITSIO License
 LICENSE_FILE=	${WRKSRC}/licenses/License.txt
 LICENSE_PERMS=	auto-accept dist-mirror dist-sell pkg-mirror pkg-sell
 
 LIB_DEPENDS=	libcurl.so:ftp/curl
 
 USES=		cpe libtool localbase pkgconfig
 
 CONFIGURE_ARGS=	--enable-reentrant --with-bzip2=/usr
 GNU_CONFIGURE=	yes
 INSTALL_TARGET=	install-strip
 USE_LDCONFIG=	yes
 
 PLIST_SUB=	PORTVERSION=${PORTVERSION}
 
 CPE_VENDOR=	nasa
 
 OPTIONS_DEFINE=	DOCS
 
 do-install-DOCS-on:
 	${MKDIR} ${STAGEDIR}${DOCSDIR}/
 	${INSTALL_DATA} ${WRKSRC}/docs/*.pdf ${STAGEDIR}${DOCSDIR}/
 
 .include <bsd.port.mk>
diff --git a/astro/cfitsio/distinfo b/astro/cfitsio/distinfo
index 5df37c53e494..7e2e48aca45c 100644
--- a/astro/cfitsio/distinfo
+++ b/astro/cfitsio/distinfo
@@ -1,3 +1,3 @@
-TIMESTAMP = 1759774515
-SHA256 (cfitsio-4.6.3.tar.gz) = fad44fff274fdda5ffcc0c0fff3bc3c596362722b9292fc8944db91187813600
-SIZE (cfitsio-4.6.3.tar.gz) = 4661924
+TIMESTAMP = 1777572474
+SHA256 (cfitsio-4.6.4.tar.gz) = 227b637b91c9820ea96f39a65eb087f053de567d82f4338e2884f123f8183c55
+SIZE (cfitsio-4.6.4.tar.gz) = 3774657
diff --git a/astro/cfitsio/files/patch-configure b/astro/cfitsio/files/patch-configure
index bf8aab7b576d..93ac212d3b00 100644
--- a/astro/cfitsio/files/patch-configure
+++ b/astro/cfitsio/files/patch-configure
@@ -1,15 +1,15 @@
 Fix build with Clang 15
 
 Reference:	https://cgit.freebsd.org/ports/commit/astro/cfitsio/Makefile?id=7eda11c87c30c735058e9393d54b631a74cf566a
 
---- configure.orig	2022-10-31 18:40:23 UTC
+--- configure.orig	2026-04-27 19:00:54 UTC
 +++ configure
-@@ -5606,8 +5606,6 @@ fi
+@@ -20564,8 +20564,6 @@ if test "x$BUILD_REENTRANT" = xyes; then
  if test "x$BUILD_REENTRANT" = xyes; then
-   printf "%s\n" "#define _REENTRANT 1" >>confdefs.h
+   printf '%s\n' "#define _REENTRANT 1" >>confdefs.h
  
--  printf "%s\n" "#define _XOPEN_SOURCE 700" >>confdefs.h
+-  printf '%s\n' "#define _XOPEN_SOURCE 700" >>confdefs.h
 -
    # Additional definition needed to get 'union semun' when using
    # _XOPEN_SOURCE on a Mac:
    if test "x$EXT" = xdarwin; then