diff --git a/javascript/ql/lib/semmle/javascript/security/dataflow/TypeConfusionThroughParameterTamperingQuery.qll b/javascript/ql/lib/semmle/javascript/security/dataflow/TypeConfusionThroughParameterTamperingQuery.qll
index 1615a69eda7..cd4c31146a8 100644
--- a/javascript/ql/lib/semmle/javascript/security/dataflow/TypeConfusionThroughParameterTamperingQuery.qll
+++ b/javascript/ql/lib/semmle/javascript/security/dataflow/TypeConfusionThroughParameterTamperingQuery.qll
@@ -26,7 +26,11 @@ class Configuration extends DataFlow::Configuration {
     sink.analyze().getAType() = TTObject()
   }
 
-  override predicate isBarrier(DataFlow::Node node) { node instanceof Barrier }
+  override predicate isBarrier(DataFlow::Node node) {
+    super.isBarrier(node)
+    or
+    node instanceof Barrier
+  }
 
   override predicate isBarrierGuard(DataFlow::BarrierGuardNode guard) {
     guard instanceof TypeOfTestBarrier or
@@ -50,7 +54,7 @@ private class TypeOfTestBarrier extends DataFlow::BarrierGuardNode, DataFlow::Va
 }
 
 private class IsArrayBarrier extends DataFlow::BarrierGuardNode, DataFlow::CallNode {
-  IsArrayBarrier() { this = DataFlow::globalVarRef("Array").getAMemberCall("isArray").getACall() }
+  IsArrayBarrier() { this = DataFlow::globalVarRef("Array").getAMemberCall("isArray") }
 
   override predicate blocks(boolean outcome, Expr e) {
     e = getArgument(0).asExpr() and
diff --git a/javascript/ql/src/change-notes/2022-09-07-type-confusion-bugfix.md b/javascript/ql/src/change-notes/2022-09-07-type-confusion-bugfix.md
new file mode 100644
index 00000000000..af351eae597
--- /dev/null
+++ b/javascript/ql/src/change-notes/2022-09-07-type-confusion-bugfix.md
@@ -0,0 +1,6 @@
+---
+category: fix
+---
+
+- Fixed a bug in the `js/type-confusion-through-parameter-tampering` query that would cause it to ignore
+  sanitizers in branching conditions. The query should now report fewer false positives.
diff --git a/javascript/ql/test/query-tests/Security/CWE-843/TypeConfusionThroughParameterTampering.expected b/javascript/ql/test/query-tests/Security/CWE-843/TypeConfusionThroughParameterTampering.expected
index 997d8968fcc..13c97e3f327 100644
--- a/javascript/ql/test/query-tests/Security/CWE-843/TypeConfusionThroughParameterTampering.expected
+++ b/javascript/ql/test/query-tests/Security/CWE-843/TypeConfusionThroughParameterTampering.expected
@@ -16,10 +16,6 @@ nodes
 | tst.js:27:5:27:7 | foo |
 | tst.js:28:5:28:7 | foo |
 | tst.js:28:5:28:7 | foo |
-| tst.js:36:9:36:11 | foo |
-| tst.js:36:9:36:11 | foo |
-| tst.js:41:5:41:7 | foo |
-| tst.js:41:5:41:7 | foo |
 | tst.js:45:9:45:35 | foo |
 | tst.js:45:15:45:35 | ctx.req ... ery.foo |
 | tst.js:45:15:45:35 | ctx.req ... ery.foo |
@@ -38,12 +34,14 @@ nodes
 | tst.js:92:9:92:16 | data.foo |
 | tst.js:92:9:92:16 | data.foo |
 | tst.js:92:9:92:16 | data.foo |
-| tst.js:95:9:95:16 | data.foo |
-| tst.js:95:9:95:16 | data.foo |
-| tst.js:95:9:95:16 | data.foo |
 | tst.js:98:9:98:16 | data.foo |
 | tst.js:98:9:98:16 | data.foo |
 | tst.js:98:9:98:16 | data.foo |
+| tst.js:103:9:103:29 | data |
+| tst.js:103:16:103:29 | req.query.data |
+| tst.js:103:16:103:29 | req.query.data |
+| tst.js:104:5:104:8 | data |
+| tst.js:104:5:104:8 | data |
 edges
 | tst.js:5:9:5:27 | foo | tst.js:6:5:6:7 | foo |
 | tst.js:5:9:5:27 | foo | tst.js:6:5:6:7 | foo |
@@ -56,10 +54,6 @@ edges
 | tst.js:5:9:5:27 | foo | tst.js:27:5:27:7 | foo |
 | tst.js:5:9:5:27 | foo | tst.js:28:5:28:7 | foo |
 | tst.js:5:9:5:27 | foo | tst.js:28:5:28:7 | foo |
-| tst.js:5:9:5:27 | foo | tst.js:36:9:36:11 | foo |
-| tst.js:5:9:5:27 | foo | tst.js:36:9:36:11 | foo |
-| tst.js:5:9:5:27 | foo | tst.js:41:5:41:7 | foo |
-| tst.js:5:9:5:27 | foo | tst.js:41:5:41:7 | foo |
 | tst.js:5:15:5:27 | req.query.foo | tst.js:5:9:5:27 | foo |
 | tst.js:5:15:5:27 | req.query.foo | tst.js:5:9:5:27 | foo |
 | tst.js:14:16:14:18 | bar | tst.js:15:9:15:11 | bar |
@@ -77,8 +71,11 @@ edges
 | tst.js:80:23:80:23 | p | tst.js:82:9:82:9 | p |
 | tst.js:90:5:90:12 | data.foo | tst.js:90:5:90:12 | data.foo |
 | tst.js:92:9:92:16 | data.foo | tst.js:92:9:92:16 | data.foo |
-| tst.js:95:9:95:16 | data.foo | tst.js:95:9:95:16 | data.foo |
 | tst.js:98:9:98:16 | data.foo | tst.js:98:9:98:16 | data.foo |
+| tst.js:103:9:103:29 | data | tst.js:104:5:104:8 | data |
+| tst.js:103:9:103:29 | data | tst.js:104:5:104:8 | data |
+| tst.js:103:16:103:29 | req.query.data | tst.js:103:9:103:29 | data |
+| tst.js:103:16:103:29 | req.query.data | tst.js:103:9:103:29 | data |
 #select
 | tst.js:6:5:6:7 | foo | tst.js:5:15:5:27 | req.query.foo | tst.js:6:5:6:7 | foo | Potential type confusion as $@ may be either an array or a string. | tst.js:5:15:5:27 | req.query.foo | this HTTP request parameter |
 | tst.js:8:5:8:7 | foo | tst.js:5:15:5:27 | req.query.foo | tst.js:8:5:8:7 | foo | Potential type confusion as $@ may be either an array or a string. | tst.js:5:15:5:27 | req.query.foo | this HTTP request parameter |
@@ -86,12 +83,10 @@ edges
 | tst.js:15:9:15:11 | bar | tst.js:5:15:5:27 | req.query.foo | tst.js:15:9:15:11 | bar | Potential type confusion as $@ may be either an array or a string. | tst.js:5:15:5:27 | req.query.foo | this HTTP request parameter |
 | tst.js:27:5:27:7 | foo | tst.js:5:15:5:27 | req.query.foo | tst.js:27:5:27:7 | foo | Potential type confusion as $@ may be either an array or a string. | tst.js:5:15:5:27 | req.query.foo | this HTTP request parameter |
 | tst.js:28:5:28:7 | foo | tst.js:5:15:5:27 | req.query.foo | tst.js:28:5:28:7 | foo | Potential type confusion as $@ may be either an array or a string. | tst.js:5:15:5:27 | req.query.foo | this HTTP request parameter |
-| tst.js:36:9:36:11 | foo | tst.js:5:15:5:27 | req.query.foo | tst.js:36:9:36:11 | foo | Potential type confusion as $@ may be either an array or a string. | tst.js:5:15:5:27 | req.query.foo | this HTTP request parameter |
-| tst.js:41:5:41:7 | foo | tst.js:5:15:5:27 | req.query.foo | tst.js:41:5:41:7 | foo | Potential type confusion as $@ may be either an array or a string. | tst.js:5:15:5:27 | req.query.foo | this HTTP request parameter |
 | tst.js:46:5:46:7 | foo | tst.js:45:15:45:35 | ctx.req ... ery.foo | tst.js:46:5:46:7 | foo | Potential type confusion as $@ may be either an array or a string. | tst.js:45:15:45:35 | ctx.req ... ery.foo | this HTTP request parameter |
 | tst.js:81:9:81:9 | p | tst.js:77:25:77:38 | req.query.path | tst.js:81:9:81:9 | p | Potential type confusion as $@ may be either an array or a string. | tst.js:77:25:77:38 | req.query.path | this HTTP request parameter |
 | tst.js:82:9:82:9 | p | tst.js:77:25:77:38 | req.query.path | tst.js:82:9:82:9 | p | Potential type confusion as $@ may be either an array or a string. | tst.js:77:25:77:38 | req.query.path | this HTTP request parameter |
 | tst.js:90:5:90:12 | data.foo | tst.js:90:5:90:12 | data.foo | tst.js:90:5:90:12 | data.foo | Potential type confusion as $@ may be either an array or a string. | tst.js:90:5:90:12 | data.foo | this HTTP request parameter |
 | tst.js:92:9:92:16 | data.foo | tst.js:92:9:92:16 | data.foo | tst.js:92:9:92:16 | data.foo | Potential type confusion as $@ may be either an array or a string. | tst.js:92:9:92:16 | data.foo | this HTTP request parameter |
-| tst.js:95:9:95:16 | data.foo | tst.js:95:9:95:16 | data.foo | tst.js:95:9:95:16 | data.foo | Potential type confusion as $@ may be either an array or a string. | tst.js:95:9:95:16 | data.foo | this HTTP request parameter |
 | tst.js:98:9:98:16 | data.foo | tst.js:98:9:98:16 | data.foo | tst.js:98:9:98:16 | data.foo | Potential type confusion as $@ may be either an array or a string. | tst.js:98:9:98:16 | data.foo | this HTTP request parameter |
+| tst.js:104:5:104:8 | data | tst.js:103:16:103:29 | req.query.data | tst.js:104:5:104:8 | data | Potential type confusion as $@ may be either an array or a string. | tst.js:103:16:103:29 | req.query.data | this HTTP request parameter |
diff --git a/javascript/ql/test/query-tests/Security/CWE-843/tst.js b/javascript/ql/test/query-tests/Security/CWE-843/tst.js
index d49f7ce53d2..3f5840b9f08 100644
--- a/javascript/ql/test/query-tests/Security/CWE-843/tst.js
+++ b/javascript/ql/test/query-tests/Security/CWE-843/tst.js
@@ -100,7 +100,8 @@ express().get('/foo', function (req, res) {
 });
 
 express().get('/foo', function (req, res) {
-    let data = req.query;
+    let data = req.query.data;
+    data.indexOf(); // NOT OK
     if (Array.isArray(data)) {
         data.indexOf(); // OK
     } else {