diff --git a/regress/usr.sbin/rpki-client/openssl/Makefile b/regress/usr.sbin/rpki-client/openssl/Makefile
index 6791481303b..3c384dcfae4 100644
--- a/regress/usr.sbin/rpki-client/openssl/Makefile
+++ b/regress/usr.sbin/rpki-client/openssl/Makefile
@@ -1,7 +1,11 @@
-# $OpenBSD: Makefile,v 1.8 2026/03/27 18:00:17 tb Exp $
+# $OpenBSD: Makefile,v 1.9 2026/03/27 19:55:35 tb Exp $
 
 EOPENSSL =	eopenssl35
 
+.if ${EOPENSSL} != "eopenssl35"
+CFLAGS += -DHAVE_X509_CRL_GET0_SIGALG
+.endif
+
 LDADD +=	-Wl,-rpath,/usr/local/lib/${EOPENSSL} -L/usr/local/lib/${EOPENSSL}
 CFLAGS +=	-I${.CURDIR}/ -I/usr/local/include/${EOPENSSL}/
 CFLAGS +=	-DOPENSSL_SUPPRESS_DEPRECATED
diff --git a/regress/usr.sbin/rpki-client/openssl/build/Makefile b/regress/usr.sbin/rpki-client/openssl/build/Makefile
index 1d99e846a94..7e18743e7ce 100644
--- a/regress/usr.sbin/rpki-client/openssl/build/Makefile
+++ b/regress/usr.sbin/rpki-client/openssl/build/Makefile
@@ -1,7 +1,11 @@
-# $OpenBSD: Makefile,v 1.5 2026/03/27 19:54:10 tb Exp $
+# $OpenBSD: Makefile,v 1.6 2026/03/27 19:55:35 tb Exp $
 
 EOPENSSL =	eopenssl35
 
+.if ${EOPENSSL} != "eopenssl35"
+CFLAGS += -DHAVE_X509_CRL_GET0_SIGALG
+.endif
+
 regress: all
 
 .if (exists(/usr/local/lib/${EOPENSSL}/libcrypto.a) && \
diff --git a/regress/usr.sbin/rpki-client/openssl/unistd.h b/regress/usr.sbin/rpki-client/openssl/unistd.h
index 638f8dab81c..396ea966ad4 100644
--- a/regress/usr.sbin/rpki-client/openssl/unistd.h
+++ b/regress/usr.sbin/rpki-client/openssl/unistd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: unistd.h,v 1.4 2025/08/19 11:31:48 job Exp $ */
+/*	$OpenBSD: unistd.h,v 1.5 2026/03/27 19:55:35 tb Exp $ */
 /*
  * Public domain
  * compatibility shim for OpenSSL 3
@@ -31,6 +31,7 @@ CMS_SignerInfo_get_version(CMS_SignerInfo *si, long *version)
 	return 1;
 }
 
+#if !HAVE_X509_CRL_GET0_SIGALG
 static inline const X509_ALGOR *
 X509_CRL_get0_tbs_sigalg(const X509_CRL *crl)
 {
@@ -39,5 +40,6 @@ X509_CRL_get0_tbs_sigalg(const X509_CRL *crl)
 	X509_CRL_get0_signature(crl, NULL, &alg);
 	return alg;
 }
+#endif
 
 #endif  /* ! RPKI_CLIENT_UNISTD_H */