diff --git a/ext/pdo_sqlite/sqlite_driver.c b/ext/pdo_sqlite/sqlite_driver.c
index c933c34ed1dcd..d9d830c4df849 100644
--- a/ext/pdo_sqlite/sqlite_driver.c
+++ b/ext/pdo_sqlite/sqlite_driver.c
@@ -737,7 +737,7 @@ static char *make_filename_safe(const char *filename)
 		}
 		return estrdup(filename);
 	}
-	if (*filename && strcmp(filename, ":memory:")) {
+	if (*filename && strncmp(filename, ":memory:", sizeof(":memory:")-1) != 0) {
 		char *fullpath = expand_filepath(filename, NULL);
 
 		if (!fullpath) {
diff --git a/ext/pdo_sqlite/tests/gh20076.phpt b/ext/pdo_sqlite/tests/gh20076.phpt
new file mode 100644
index 0000000000000..c32fdde985ac9
--- /dev/null
+++ b/ext/pdo_sqlite/tests/gh20076.phpt
@@ -0,0 +1,13 @@
+--TEST--
+GH-20076 (open_basedir prohibits opening :memory:?cache=shared)
+--EXTENSIONS--
+sqlite3
+--INI--
+open_basedir=xx
+--FILE--
+<?php
+var_dump(new PDO("sqlite::memory:?cache=shared"));
+?>
+--EXPECT--
+object(PDO)#1 (0) {
+}
diff --git a/ext/sqlite3/sqlite3.c b/ext/sqlite3/sqlite3.c
index 9b3286b70220d..e3a2332f60821 100644
--- a/ext/sqlite3/sqlite3.c
+++ b/ext/sqlite3/sqlite3.c
@@ -113,7 +113,7 @@ PHP_METHOD(SQLite3, open)
 		RETURN_THROWS();
 	}
 
-	if (filename_len != 0 && (filename_len != sizeof(":memory:")-1 ||
+	if (filename_len != 0 && (filename_len < sizeof(":memory:")-1 ||
 			memcmp(filename, ":memory:", sizeof(":memory:")-1) != 0)) {
 		if (!(fullpath = expand_filepath(filename, NULL))) {
 			zend_throw_exception(zend_ce_exception, "Unable to expand filepath", 0);
@@ -126,7 +126,7 @@ PHP_METHOD(SQLite3, open)
 			RETURN_THROWS();
 		}
 	} else {
-		/* filename equals "" or ":memory:" */
+		/* filename equals "" or starts with ":memory:" */
 		fullpath = filename;
 	}
 
diff --git a/ext/sqlite3/tests/gh20076.phpt b/ext/sqlite3/tests/gh20076.phpt
new file mode 100644
index 0000000000000..406d7955debb9
--- /dev/null
+++ b/ext/sqlite3/tests/gh20076.phpt
@@ -0,0 +1,13 @@
+--TEST--
+GH-20076 (open_basedir prohibits opening :memory:?cache=shared)
+--EXTENSIONS--
+sqlite3
+--INI--
+open_basedir=xx
+--FILE--
+<?php
+var_dump(new SQLite3(":memory:?cache=shared"));
+?>
+--EXPECT--
+object(SQLite3)#1 (0) {
+}