diff --git a/build.gradle.kts b/build.gradle.kts
index b41c75e284..9baf84708c 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -80,10 +80,10 @@ allprojects {
             implementation("io.netty:netty-codec-http2:4.2.5.Final") {
                 because("Version 4.1.123.Final vulnerability: https://www.cve.org/CVERecord?id=CVE-2025-8916")
             }
-            testImplementation("com.networknt:json-schema-validator:1.5.8") {
+            testImplementation("com.networknt:json-schema-validator:1.5.9") {
                 because("There's a conflict between mockserver-netty and identity-hub dependencies for testing, forcing json-schema-validator to 1.5.6 is solving that.")
             }
-            testFixturesApi("com.networknt:json-schema-validator:1.5.8") {
+            testFixturesApi("com.networknt:json-schema-validator:1.5.9") {
                 because("There's a conflict between mockserver-netty and identity-hub dependencies for testing, forcing json-schema-validator to 1.5.6 is solving that.")
             }
         }
diff --git a/edc-extensions/cx-policy/build.gradle.kts b/edc-extensions/cx-policy/build.gradle.kts
index 5b681f2d18..e57f82b063 100644
--- a/edc-extensions/cx-policy/build.gradle.kts
+++ b/edc-extensions/cx-policy/build.gradle.kts
@@ -43,8 +43,8 @@ dependencies {
     implementation(libs.edc.lib.validator)
 
     testImplementation(libs.edc.junit)
-    implementation("com.networknt:json-schema-validator:1.5.6") {
-        because("There's a conflict between mockserver-netty and identity-hub dependencies for testing, forcing json-schema-validator to 1.5.6 is solving that.")
+    implementation("com.networknt:json-schema-validator:1.5.9") {
+        because("There's a conflict between mockserver-netty and identity-hub dependencies for testing, forcing json-schema-validator to 1.5.9 is solving that.")
     }
     testFixturesImplementation(libs.edc.junit)
     testFixturesImplementation(libs.edc.spi.jsonld)
diff --git a/edc-tests/e2e/dcp-tck-tests/build.gradle.kts b/edc-tests/e2e/dcp-tck-tests/build.gradle.kts
index aa79fb0d37..23210036ed 100644
--- a/edc-tests/e2e/dcp-tck-tests/build.gradle.kts
+++ b/edc-tests/e2e/dcp-tck-tests/build.gradle.kts
@@ -25,7 +25,7 @@ dependencies {
 
     constraints {
         // netty's mockserver depends on an older version of the json schema validator, but TCK needs this:
-        implementation("com.networknt:json-schema-validator:1.5.8") {
+        implementation("com.networknt:json-schema-validator:1.5.9") {
             because("This version is required by the TCK")
         }
     }