diff --git a/dlls/crypt32/crypt32.spec b/dlls/crypt32/crypt32.spec
index bae473c01af..12e1223ab87 100644
--- a/dlls/crypt32/crypt32.spec
+++ b/dlls/crypt32/crypt32.spec
@@ -122,7 +122,7 @@
 @ stub CryptGetAsyncParam
 @ stdcall CryptGetDefaultOIDDllList(long long ptr ptr)
 @ stdcall CryptGetDefaultOIDFunctionAddress(long long wstr long ptr ptr)
-@ stub CryptGetMessageCertificates
+@ stdcall CryptGetMessageCertificates(long ptr long ptr long)
 @ stub CryptGetMessageSignerCount
 @ stdcall CryptGetOIDFunctionAddress(long long str long ptr ptr)
 @ stdcall CryptGetOIDFunctionValue(long str str wstr ptr ptr ptr)
diff --git a/dlls/crypt32/msg.c b/dlls/crypt32/msg.c
index c9226addb73..97c6b4e0c5d 100644
--- a/dlls/crypt32/msg.c
+++ b/dlls/crypt32/msg.c
@@ -2273,3 +2273,16 @@ BOOL WINAPI CryptMsgControl(HCRYPTMSG hCryptMsg, DWORD dwFlags,
      pvCtrlPara);
     return msg->control(hCryptMsg, dwFlags, dwCtrlType, pvCtrlPara);
 }
+
+HCERTSTORE WINAPI CryptGetMessageCertificates(DWORD dwMsgAndCertEncodingType,
+ HCRYPTPROV_LEGACY hCryptProv, DWORD dwFlags, const BYTE* pbSignedBlob,
+ DWORD cbSignedBlob)
+{
+    CRYPT_DATA_BLOB blob = { cbSignedBlob, (LPBYTE)pbSignedBlob };
+
+    TRACE("(%08x, %ld, %d08x %p, %d)\n", dwMsgAndCertEncodingType, hCryptProv,
+     dwFlags, pbSignedBlob, cbSignedBlob);
+
+    return CertOpenStore(CERT_STORE_PROV_PKCS7, dwMsgAndCertEncodingType,
+     hCryptProv, dwFlags, &blob);
+}