diff --git a/pkgs/tools/networking/openssh/common.nix b/pkgs/tools/networking/openssh/common.nix
index 052dbc7ba215..1a4cd2f9e9fe 100644
--- a/pkgs/tools/networking/openssh/common.nix
+++ b/pkgs/tools/networking/openssh/common.nix
@@ -65,6 +65,10 @@ stdenv.mkDerivation (finalAttrs: {
 
     # See discussion in https://github.com/NixOS/nixpkgs/pull/16966
     ./dont_create_privsep_path.patch
+
+    # See discussion in https://github.com/NixOS/nixpkgs/issues/453782 and
+    # https://github.com/openssh/openssh-portable/pull/602
+    ./fix_pkcs11_tests.patch
   ]
   ++ extraPatches;
 
@@ -148,8 +152,7 @@ stdenv.mkDerivation (finalAttrs: {
     openssl
   ]
   ++ lib.optional (!stdenv.hostPlatform.isDarwin) hostname
-  # TODO: softhsm is currently breaking the tests; see #453782
-  ++ lib.optional (false && !stdenv.hostPlatform.isDarwin && !stdenv.hostPlatform.isMusl) softhsm;
+  ++ lib.optional (!stdenv.hostPlatform.isDarwin && !stdenv.hostPlatform.isMusl) softhsm;
 
   preCheck = lib.optionalString (stdenv.buildPlatform.canExecute stdenv.hostPlatform) (
     ''
@@ -198,15 +201,11 @@ stdenv.mkDerivation (finalAttrs: {
       # set up NIX_REDIRECTS for direct invocations
       set -a; source ~/.ssh/environment.base; set +a
     ''
-    # See softhsm in nativeCheckInputs above.
-    +
-      lib.optionalString
-        (!finalAttrs.doCheck && !stdenv.hostPlatform.isDarwin && !stdenv.hostPlatform.isMusl)
-        ''
-          # The extra tests check PKCS#11 interactions, which softhsm emulates with software only
-          substituteInPlace regress/test-exec.sh \
-            --replace-fail /usr/local/lib/softhsm/libsofthsm2.so ${lib.getLib softhsm}/lib/softhsm/libsofthsm2.so
-        ''
+    + lib.optionalString (!stdenv.hostPlatform.isDarwin && !stdenv.hostPlatform.isMusl) ''
+      # The extra tests check PKCS#11 interactions, which softhsm emulates with software only
+      substituteInPlace regress/test-exec.sh \
+        --replace-fail /usr/local/lib/softhsm/libsofthsm2.so ${lib.getLib softhsm}/lib/softhsm/libsofthsm2.so
+    ''
   );
   # integration tests hard to get working on darwin with its shaky
   # sandbox
diff --git a/pkgs/tools/networking/openssh/fix_pkcs11_tests.patch b/pkgs/tools/networking/openssh/fix_pkcs11_tests.patch
new file mode 100644
index 000000000000..c4459c8ee0e1
--- /dev/null
+++ b/pkgs/tools/networking/openssh/fix_pkcs11_tests.patch
@@ -0,0 +1,51 @@
+From 642218d8dd1ec79fa0c8db491fd46faa3ab026f7 Mon Sep 17 00:00:00 2001
+From: Morgan Jones <me@numin.it>
+Date: Tue, 21 Oct 2025 01:15:55 -0700
+Subject: [PATCH 1/2] test-exec: use -P for allowed PKCS#11 library when
+ starting agent
+
+If we just loaded a PKCS#11 library, we should allow it so the
+regression test can run.
+
+Fixes: https://github.com/NixOS/nixpkgs/issues/453782
+---
+ regress/test-exec.sh | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/regress/test-exec.sh b/regress/test-exec.sh
+index 5b0c91f3faa..30b3da8709d 100644
+--- a/regress/test-exec.sh
++++ b/regress/test-exec.sh
+@@ -1023,6 +1023,9 @@ p11_ssh_add() {
+ 
+ start_ssh_agent() {
+ 	EXTRA_AGENT_ARGS="$1"
++	if [ "$PKCS11_OK" = "yes" ]; then
++		EXTRA_AGENT_ARGS="${EXTRA_AGENT_ARGS} -P${TEST_SSH_PKCS11}"
++	fi
+ 	SSH_AUTH_SOCK="$OBJ/agent.sock"
+ 	export SSH_AUTH_SOCK
+ 	rm -f $SSH_AUTH_SOCK $OBJ/agent.log
+
+From 5ae735db7d81b38ee059d63a4011291cb4456aef Mon Sep 17 00:00:00 2001
+From: Morgan Jones <me@numin.it>
+Date: Tue, 21 Oct 2025 01:50:23 -0700
+Subject: [PATCH 2/2] test-exec: give more time for ssh-agent to start
+
+---
+ regress/test-exec.sh | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/regress/test-exec.sh b/regress/test-exec.sh
+index 30b3da8709d..56a7653b386 100644
+--- a/regress/test-exec.sh
++++ b/regress/test-exec.sh
+@@ -1034,7 +1034,7 @@ start_ssh_agent() {
+ 	    > $OBJ/agent.log 2>&1 &
+ 	AGENT_PID=$!
+ 	trap "kill $AGENT_PID" EXIT
+-	for x in 0 1 2 3 4 ; do
++	for x in $(seq 15); do
+ 		# Give it a chance to start
+ 		${SSHADD} -l > /dev/null 2>&1
+ 		r=$?