diff --git a/src/java.base/share/classes/sun/security/pkcs/SignerInfo.java b/src/java.base/share/classes/sun/security/pkcs/SignerInfo.java
index c3e0fe92874..39cd90c56ab 100644
--- a/src/java.base/share/classes/sun/security/pkcs/SignerInfo.java
+++ b/src/java.base/share/classes/sun/security/pkcs/SignerInfo.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1996, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1996, 2023, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -537,7 +537,16 @@ public class SignerInfo implements DerEncoder {
                     digAlg = "SHA" + digAlg.substring(4);
                 }
                 if (keyAlg.equals("EC")) keyAlg = "ECDSA";
-                return digAlg + "with" + keyAlg;
+                String sigAlg = digAlg + "with" + keyAlg;
+                try {
+                    Signature.getInstance(sigAlg);
+                    return sigAlg;
+                } catch (NoSuchAlgorithmException e) {
+                    // Possibly an unknown modern signature algorithm,
+                    // in this case, encAlg should already be a signature
+                    // algorithm.
+                    return encAlg;
+                }
         }
     }
 
diff --git a/test/jdk/sun/security/pkcs/pkcs7/NewSigAlg.java b/test/jdk/sun/security/pkcs/pkcs7/NewSigAlg.java
new file mode 100644
index 00000000000..098dd9caaa4
--- /dev/null
+++ b/test/jdk/sun/security/pkcs/pkcs7/NewSigAlg.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8299746
+ * @summary Accept unknown signatureAlgorithm in PKCS7 SignerInfo
+ * @modules java.base/sun.security.pkcs
+ *          java.base/sun.security.x509
+ * @library /test/lib
+ */
+
+import jdk.test.lib.Asserts;
+import sun.security.pkcs.SignerInfo;
+import sun.security.x509.AlgorithmId;
+
+public class NewSigAlg {
+    public static void main(String[] args) throws Exception {
+        test("SHA-1", "RSA", "SHA1withRSA");
+        test("SHA-1", "SHA1withRSA", "SHA1withRSA");
+        test("SHA-1", "SHA256withRSA", "SHA1withRSA");
+        // Sorry I have to use something that has an OID but not known
+        // as a signature algorithm.
+        test("SHA-1", "PBES2", "PBES2");
+    }
+
+    static void test(String d, String e, String s) throws Exception {
+        Asserts.assertEQ(s, SignerInfo.makeSigAlg(
+                AlgorithmId.get(d), AlgorithmId.get(s), false));
+    }
+}