diff --git a/ssh-agent.c b/ssh-agent.c

index 618bb198..8ea831f4 100644

diff -up openssh-9.3p1/ssh-agent.c.cve openssh-9.3p1/ssh-agent.c

--- openssh-9.3p1/ssh-agent.c.cve	2023-07-21 15:38:13.237276580 +0200

+++ openssh-9.3p1/ssh-agent.c	2023-07-21 15:41:30.269943569 +0200

@@ -169,6 +169,12 @@ char socket_dir[PATH_MAX];

 /* Pattern-list of allowed PKCS#11/Security key paths */

 static char *allowed_providers;

+/*

+ * Allows PKCS11 providers or SK keys that use non-internal providers to

+ * be added over a remote connection (identified by session-bind@openssh.com).

+ */

+static int remote_add_provider;

+

 /* locking */

 #define LOCK_SIZE	32

 #define LOCK_SALT_SIZE	16

@@ -1228,6 +1234,12 @@ process_add_identity(SocketEntry *e)

 		if (strcasecmp(sk_provider, "internal") == 0) {

 			debug_f("internal provider");

 		} else {

+			if (e->nsession_ids != 0 && !remote_add_provider) {

+				verbose("failed add of SK provider \"%.100s\": "

+				    "remote addition of providers is disabled",

+				    sk_provider);

+				goto out;

+			}

 			if (realpath(sk_provider, canonical_provider) == NULL) {

 				verbose("failed provider \"%.100s\": "

 				    "realpath: %s", sk_provider,

@@ -1368,7 +1380,7 @@ no_identities(SocketEntry *e)

 #ifdef ENABLE_PKCS11

 static char *

-sanitize_pkcs11_provider(const char *provider)

+sanitize_pkcs11_provider(SocketEntry *e, const char *provider)

 {

 	struct pkcs11_uri *uri = NULL;

 	char *sane_uri, *module_path = NULL; /* default path */

@@ -1399,6 +1411,11 @@ sanitize_pkcs11_provider(const char *pro

 		module_path = strdup(provider); /* simple path */

 	if (module_path != NULL) { /* do not validate default NULL path in URI */

+		if (e->nsession_ids != 0 && !remote_add_provider) {

+			verbose("failed PKCS#11 add of \"%.100s\": remote addition of "

+			    "providers is disabled", provider);

+			return NULL;

+		}

 		if (realpath(module_path, canonical_provider) == NULL) {

 			verbose("failed PKCS#11 provider \"%.100s\": realpath: %s",

 			    module_path, strerror(errno));

@@ -1455,7 +1472,7 @@ process_add_smartcard_key(SocketEntry *e

 		goto send;

 	}

-	sane_uri = sanitize_pkcs11_provider(provider);

+	sane_uri = sanitize_pkcs11_provider(e, provider);

 	if (sane_uri == NULL)

 		goto send;

@@ -1516,7 +1533,7 @@ process_remove_smartcard_key(SocketEntry

 	}

 	free(pin);

-	sane_uri = sanitize_pkcs11_provider(provider);

+	sane_uri = sanitize_pkcs11_provider(e, provider);

 	if (sane_uri == NULL)

 		goto send;

@@ -2108,7 +2125,9 @@ main(int ac, char **av)

 			break;

 		case 'O':

 			if (strcmp(optarg, "no-restrict-websafe") == 0)

-				restrict_websafe  = 0;

+				restrict_websafe = 0;

+			else if (strcmp(optarg, "allow-remote-pkcs11") == 0)

+				remote_add_provider = 1;

 			else

 				fatal("Unknown -O option");

 			break;

diff --git a/ssh-pkcs11.c b/ssh-pkcs11.c

index 6be647ec..ebddf6c3 100644

--- a/ssh-pkcs11.c

+++ b/ssh-pkcs11.c

@@ -1537,10 +1537,8 @@ pkcs11_register_provider(char *provider_id, char *pin,

 		error("dlopen %s failed: %s", provider_module, dlerror());

 		goto fail;

 	}

-	if ((getfunctionlist = dlsym(handle, "C_GetFunctionList")) == NULL) {

-		error("dlsym(C_GetFunctionList) failed: %s", dlerror());

-		goto fail;

-	}

+	if ((getfunctionlist = dlsym(handle, "C_GetFunctionList")) == NULL)

+		fatal("dlsym(C_GetFunctionList) failed: %s", dlerror());

 	p->module->handle = handle;

 	/* setup the pkcs11 callbacks */

--- a/ssh-agent.1	2023-03-15 22:28:19.000000000 +0100

+++ b/ssh-agent.1	2023-07-19 21:39:17.981406432 +0200

@@ -107,9 +107,27 @@

 .It Fl O Ar option

 Specify an option when starting

 .Nm .

-Currently only one option is supported:

+Currently two options are supported:

+.Cm allow-remote-pkcs11

+and

 .Cm no-restrict-websafe .

-This instructs

+.Pp

+The

+.Cm allow-remote-pkcs11

+option allows clients of a forwarded

+.Nm

+to load PKCS#11 or FIDO provider libraries.

+By default only local clients may perform this operation.

+Note that signalling that a

+.Nm

+client remote is performed by

+.Xr ssh 1 ,

+and use of other tools to forward access to the agent socket may circumvent

+this restriction.

+.Pp

+The

+.Cm no-restrict-websafe ,

+instructs

 .Nm

 to permit signatures using FIDO keys that might be web authentication

 requests.