diff --git a/src/project/manifest.rs b/src/project/manifest.rs
index fc8666ef1..98773a27d 100644
--- a/src/project/manifest.rs
+++ b/src/project/manifest.rs
@@ -17,6 +17,7 @@ use url::Url;
 /// Describes the contents of a project manifest.
 #[serde_as]
 #[derive(Debug, Clone, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct ProjectManifest {
     /// Information about the project
     pub project: ProjectMetadata,
@@ -177,6 +178,7 @@ impl<'de> Deserialize<'de> for TargetSelector {
 
 #[serde_as]
 #[derive(Debug, Clone, Default, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct TargetMetadata {
     /// Target specific dependencies
     #[serde(default)]
diff --git a/src/task/mod.rs b/src/task/mod.rs
index bd9e70195..75677a0f0 100644
--- a/src/task/mod.rs
+++ b/src/task/mod.rs
@@ -87,6 +87,7 @@ impl Task {
 /// A command script executes a single command from the environment
 #[serde_as]
 #[derive(Debug, Clone, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct Execute {
     /// A list of arguments, the first argument denotes the command to run. When deserializing both
     /// an array of strings and a single string are supported.