diff --git a/lib/vtls/x509asn1.c b/lib/vtls/x509asn1.c
index 2ab74cadf6..4c5dac3e8b 100644
--- a/lib/vtls/x509asn1.c
+++ b/lib/vtls/x509asn1.c
@@ -1062,7 +1062,7 @@ static int do_pubkey(struct Curl_easy *data, int certnum, const char *algo,
if(p) {
if(do_pubkey_field(data, certnum, "dh(p)", &elem))
return 1;
- if(getASN1Element(&elem, param->beg, param->end)) {
+ if(getASN1Element(&elem, p, param->end)) {
if(do_pubkey_field(data, certnum, "dh(g)", &elem))
return 1;
if(do_pubkey_field(data, certnum, "dh(pub_key)", &pk))
diff --git a/tests/data/Makefile.am b/tests/data/Makefile.am
index ec9620b9cd..bd3f0d01b0 100644
--- a/tests/data/Makefile.am
+++ b/tests/data/Makefile.am
@@ -223,7 +223,7 @@ test1650 test1651 test1652 test1653 test1654 test1655 test1656 test1657 \
test1658 test1659 test1660 test1661 test1662 test1663 test1664 test1665 \
test1666 test1667 test1668 test1669 \
\
-test1670 test1671 test1672 test1673 test1674 test1675 \
+test1670 test1671 test1672 test1673 test1674 test1675 test1676 \
\
test1680 test1681 test1682 test1683 test1684 test1685 \
\
diff --git a/tests/data/test1676 b/tests/data/test1676
new file mode 100644
index 0000000000..7f4907fea3
--- /dev/null
+++ b/tests/data/test1676
@@ -0,0 +1,21 @@
+
+
+
+
+unittest
+x509
+DH
+
+
+
+# Client-side
+
+
+unittest
+
+
+x509 DH public key parameter extraction
+
+
+
+
diff --git a/tests/unit/Makefile.inc b/tests/unit/Makefile.inc
index f0ce3d4eef..b474f3d7fc 100644
--- a/tests/unit/Makefile.inc
+++ b/tests/unit/Makefile.inc
@@ -42,7 +42,7 @@ TESTS_C = \
unit1650.c unit1651.c unit1652.c unit1653.c unit1654.c unit1655.c unit1656.c \
unit1657.c unit1658.c unit1660.c unit1661.c unit1663.c unit1664.c \
unit1666.c unit1667.c unit1668.c unit1669.c \
- unit1674.c unit1675.c \
+ unit1674.c unit1675.c unit1676.c \
unit1979.c unit1980.c \
unit2600.c unit2601.c unit2602.c unit2603.c unit2604.c unit2605.c \
unit3200.c unit3205.c \
diff --git a/tests/unit/unit1676.c b/tests/unit/unit1676.c
new file mode 100644
index 0000000000..3cc80b9cb6
--- /dev/null
+++ b/tests/unit/unit1676.c
@@ -0,0 +1,120 @@
+/***************************************************************************
+ * _ _ ____ _
+ * Project ___| | | | _ \| |
+ * / __| | | | |_) | |
+ * | (__| |_| | _ <| |___
+ * \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) Daniel Stenberg, , et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * SPDX-License-Identifier: curl
+ *
+ ***************************************************************************/
+#include "unitcheck.h"
+#include "vtls/x509asn1.h"
+#include "vtls/vtls.h"
+
+static CURLcode test_unit1676(const char *arg)
+{
+ UNITTEST_BEGIN_SIMPLE
+
+#if defined(USE_GNUTLS) || defined(USE_MBEDTLS) || defined(USE_RUSTLS) || \
+ defined(USE_SCHANNEL)
+
+ /*
+ * Minimal DER-encoded X.509 certificate with a DH public key.
+ * Hand-crafted to exercise the do_pubkey() dhpublicnumber branch.
+ *
+ * The DH parameters contain two distinct INTEGER values:
+ * p = 0x11 (renders as "17" via int2str decimal format)
+ * g = 0x22 (renders as "34")
+ * The public key value is:
+ * pub_key = 0x33 (renders as "51")
+ *
+ * OID 1.2.840.10046.2.1 = dhpublicnumber
+ */
+ static const unsigned char cert[] = {
+ 0x30, 0x81, 0x85, 0x30, 0x72, 0xA0, 0x03, 0x02, 0x01, 0x02, 0x02, 0x01,
+ 0x01, 0x30, 0x0B, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01,
+ 0x01, 0x0B, 0x30, 0x0F, 0x31, 0x0D, 0x30, 0x0B, 0x06, 0x03, 0x55, 0x04,
+ 0x03, 0x0C, 0x04, 0x74, 0x65, 0x73, 0x74, 0x30, 0x1E, 0x17, 0x0D, 0x32,
+ 0x35, 0x30, 0x31, 0x30, 0x31, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x5A,
+ 0x17, 0x0D, 0x32, 0x36, 0x30, 0x31, 0x30, 0x31, 0x30, 0x30, 0x30, 0x30,
+ 0x30, 0x30, 0x5A, 0x30, 0x0F, 0x31, 0x0D, 0x30, 0x0B, 0x06, 0x03, 0x55,
+ 0x04, 0x03, 0x0C, 0x04, 0x74, 0x65, 0x73, 0x74, 0x30, 0x19, 0x30, 0x11,
+ 0x06, 0x07, 0x2A, 0x86, 0x48, 0xCE, 0x3E, 0x02, 0x01, 0x30, 0x06, 0x02,
+ 0x01, 0x11, 0x02, 0x01, 0x22, 0x03, 0x04, 0x00, 0x02, 0x01, 0x33, 0x30,
+ 0x0B, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0B,
+ 0x03, 0x02, 0x00, 0xFF
+ };
+
+ CURLcode result;
+ const char *beg = (const char *)&cert[0];
+ const char *end = (const char *)&cert[sizeof(cert)];
+ struct Curl_easy *data;
+ struct curl_slist *slist;
+ const char *dhp_value = NULL;
+ const char *dhg_value = NULL;
+ const char *dhpk_value = NULL;
+
+ if(curl_global_init(CURL_GLOBAL_ALL) != CURLE_OK) {
+ curl_mfprintf(stderr, "curl_global_init() failed\n");
+ return TEST_ERR_MAJOR_BAD;
+ }
+
+ data = curl_easy_init();
+ if(!data) {
+ curl_global_cleanup();
+ return TEST_ERR_MAJOR_BAD;
+ }
+
+ data->set.ssl.certinfo = 1;
+ result = Curl_ssl_init_certinfo(data, 1);
+ if(result) {
+ curl_easy_cleanup(data);
+ curl_global_cleanup();
+ return TEST_ERR_MAJOR_BAD;
+ }
+
+ result = Curl_extract_certinfo(data, 0, beg, end);
+ fail_unless(result == CURLE_OK, "Curl_extract_certinfo returned error");
+ if(result == CURLE_OK) {
+ /* Walk certinfo entries to find dh(p), dh(g), and dh(pub_key) */
+ for(slist = data->info.certs.certinfo[0]; slist; slist = slist->next) {
+ if(strncmp(slist->data, "dh(p):", 6) == 0)
+ dhp_value = slist->data + 6;
+ else if(strncmp(slist->data, "dh(g):", 6) == 0)
+ dhg_value = slist->data + 6;
+ else if(strncmp(slist->data, "dh(pub_key):", 12) == 0)
+ dhpk_value = slist->data + 12;
+ }
+
+ abort_unless(dhp_value != NULL, "dh(p) not found in certinfo");
+ abort_unless(dhg_value != NULL, "dh(g) not found in certinfo");
+ abort_unless(dhpk_value != NULL, "dh(pub_key) not found in certinfo");
+ fail_if(strcmp(dhp_value, dhg_value) == 0,
+ "dh(p) and dh(g) have the same value (bug: g re-reads p)");
+ fail_unless(strcmp(dhp_value, "17") == 0, "dh(p) expected 17 (0x11)");
+ fail_unless(strcmp(dhg_value, "34") == 0, "dh(g) expected 34 (0x22)");
+ fail_unless(strcmp(dhpk_value, "51") == 0,
+ "dh(pub_key) expected 51 (0x33)");
+ }
+
+ curl_easy_cleanup(data);
+ curl_global_cleanup();
+#else
+ puts("not tested since Curl_extract_certinfo() is not built in");
+#endif
+ UNITTEST_END_SIMPLE
+}