diff --git a/libreswan-4.15-CVE-2026-50721.patch b/libreswan-4.15-CVE-2026-50721.patch
new file mode 100644
index 0000000000000000000000000000000000000000..fa95367c8366bd594843efa3b3760ff4bbec46bf
--- /dev/null
+++ b/libreswan-4.15-CVE-2026-50721.patch
@@ -0,0 +1,81 @@
+From e06415f5c66bfaba5c43c04b7e312f57912cb1cc Mon Sep 17 00:00:00 2001
+From: Andrew Cagney <cagney@gnu.org>
+Date: Thu, 9 Apr 2026 21:02:51 -0400
+Subject: [PATCH] crypto: in RSA_authenticate_hash_signature_raw_rsa() use
+ PK11_Verify()
+
+---
+ lib/libswan/pubkey_rsa.c | 51 +++++-----------------------------------
+ 1 file changed, 6 insertions(+), 45 deletions(-)
+
+Adapted-by: PkgAgent/deepseek-v4 (modified to adapt to opencloudos-stream)
+
+diff --git a/lib/libswan/pubkey_rsa.c b/lib/libswan/pubkey_rsa.c
+index 38b44ab..0de17c2 100644
+--- a/lib/libswan/pubkey_rsa.c
++++ b/lib/libswan/pubkey_rsa.c
+@@ -402,58 +402,19 @@ static bool RSA_authenticate_signature_raw_rsa(const struct crypt_mac *expected_
+ 			      *expected_hash);
+ 	}
+ 
+-	/*
+-	 * Use the same space used by the out going hash.
+-	 */
+-
+-	SECItem decrypted_signature = {
+-		.type = siBuffer,
+-	};
+-
+-	if (SECITEM_AllocItem(NULL, &decrypted_signature, signature.len) == NULL) {
+-		llog_nss_error(RC_LOG, logger, "allocating space for decrypted RSA signature");
+-		return false;
+-	}
+-
+ 	/* NSS doesn't do const */
+-	const SECItem encrypted_signature = {
+-		.type = siBuffer,
+-		.data = DISCARD_CONST(unsigned char *, signature.ptr),
+-		.len  = signature.len,
+-	};
++	const SECItem signature_secitem =
++		same_shunk_as_secitem(signature, siBuffer);
++	const SECItem expected_hash_secitem =
++		same_shunk_as_secitem(HUNK_AS_SHUNK(*expected_hash), siBuffer);
+ 
+-	if (PK11_VerifyRecover(seckey_public, &encrypted_signature, &decrypted_signature,
+-			       lsw_nss_get_password_context(logger)) != SECSuccess) {
+-		SECITEM_FreeItem(&decrypted_signature, PR_FALSE/*not-pointer*/);
++	if (PK11_Verify(seckey_public, &signature_secitem, &expected_hash_secitem,
++			lsw_nss_get_password_context(logger)) != SECSuccess) {
+ 		dbg("NSS RSA verify: decrypting signature is failed");
+ 		*fatal_diag = NULL;
+ 		return false;
+ 	}
+ 
+-	if (DBGP(DBG_CRYPT)) {
+-		LLOG_JAMBUF(DEBUG_STREAM, logger, buf) {
+-			jam_string(buf, "NSS RSA verify: decrypted sig: ");
+-			jam_nss_secitem(buf, &decrypted_signature);
+-		}
+-	}
+-
+-	/*
+-	 * Expect the matching hash to appear at the end.  See above
+-	 * for length check.  It may, or may not, be prefixed by a
+-	 * PKCS#1 1.5 RSA ASN.1 blob.
+-	 */
+-	passert(decrypted_signature.len >= expected_hash->len);
+-	uint8_t *start = (decrypted_signature.data
+-			  + decrypted_signature.len
+-			  - expected_hash->len);
+-	if (!memeq(start, expected_hash->ptr, expected_hash->len)) {
+-		dbg("RSA Signature NOT verified");
+-		SECITEM_FreeItem(&decrypted_signature, PR_FALSE/*not-pointer*/);
+-		*fatal_diag = NULL;
+-		return false;
+-	}
+-
+-	SECITEM_FreeItem(&decrypted_signature, PR_FALSE/*not-pointer*/);
+ 	*fatal_diag = NULL;
+ 	return true;
+ }
diff --git a/libreswan.spec b/libreswan.spec
index 449a641b8b397b109423e49bb37dd945ae0dc4b5..35b14a63090cf682a20b2391b60575b3a2665df6 100644
--- a/libreswan.spec
+++ b/libreswan.spec
@@ -24,7 +24,7 @@
 Summary: Internet Key Exchange (IKEv1 and IKEv2) implementation for IPsec
 Name:    libreswan
 Version: 4.15
-Release: 5%{?dist}
+Release: 6%{?dist}
 License: GPL-2.0-or-later
 Url:     https://github.com/libreswan/libreswan
 Source0: %{url}/archive/refs/tags/v%{version}.tar.gz
@@ -38,6 +38,7 @@ Source4: 50-libreswan.conf
 
 # Security fixes
 Patch0001: libreswan-4.15-CVE-2026-12413.patch
+Patch0002: libreswan-4.15-CVE-2026-50721.patch
 
 BuildRequires: audit-libs-devel bison curl-devel flex gcc gnupg2 hostname ldns-devel
 BuildRequires: libcap-ng-devel libevent-devel libseccomp-devel libselinux-devel make
@@ -163,6 +164,10 @@ certutil -N -d sql:$tmpdir --empty-password
 %doc %{_mandir}/*/*
 
 %changelog
+* Tue Aug 04 2026 PkgAgent Robot <pkgagent@opencloudos.tech> - 4.15-6
+- [Type] security
+- [DESC] Fix CVE-2026-50721: insufficient hash length validation in RSA_authenticate_hash_signature_raw_rsa() leads to signature forgery/DoS
+
 * Mon Jul 06 2026 PkgAgent Robot <pkgagent@opencloudos.tech> - 4.15-5
 - [Type] security
 - [DESC] Fix CVE-2026-12413: off-by-one error in reassemble_v2_incoming_fragments() causes denial of service