diff --git a/net/http/do.ha b/net/http/do.ha
index c68cb9b..5fa21ca 100644
--- a/net/http/do.ha
+++ b/net/http/do.ha
@@ -1,5 +1,6 @@
 use bufio;
 use encoding::utf8;
+use errors;
 use fmt;
 use io;
 use net::dial;
@@ -43,7 +44,6 @@ export fn do(client: *client, req: *request) (response | error) = {
 		yield;
 	};
 
-	// TODO: Improve error handling
 	let resp = response { ... };
 	const scan = bufio::newscanner_static(conn, buf);
 	read_statusline(&resp, &scan)?;
@@ -64,32 +64,52 @@ export fn do(client: *client, req: *request) (response | error) = {
 fn read_statusline(
 	resp: *response,
 	scan: *bufio::scanner,
-) (void | io::error) = {
+) (void | error) = {
 	const status = match (bufio::scan_string(scan, "\r\n")) {
 	case let line: const str =>
 		yield line;
 	case let err: io::error =>
 		return err;
 	case utf8::invalid =>
-		abort(); // TODO
+		return protoerr;
 	case io::EOF =>
-		abort(); // TODO
+		return protoerr;
 	};
 
-	// TODO: Error handling
 	const tok = strings::tokenize(status, " ");
-	const version = strings::next_token(&tok) as str;
-	const status = strings::next_token(&tok) as str;
-	const reason = strings::next_token(&tok) as str;
 
-	assert(version == "HTTP/1.1"); // TODO
+	const version = match (strings::next_token(&tok)) {
+	case let ver: str =>
+		yield ver;
+	case void =>
+		return protoerr;
+	};
+
+	const status = match (strings::next_token(&tok)) {
+	case let status: str =>
+		yield status;
+	case void =>
+		return protoerr;
+	};
+
+	const reason = match (strings::next_token(&tok)) {
+	case let reason: str =>
+		yield reason;
+	case void =>
+		return protoerr;
+	};
+
 	const (_, version) = strings::cut(version, "/");
 	const (major, minor) = strings::cut(version, ".");
-
 	resp.version = (
 		strconv::stou(major)!,
 		strconv::stou(minor)!,
 	);
+
+	if (resp.version.0 > 1) {
+		return errors::unsupported;
+	};
+
 	resp.status = strconv::stou(status)!;
 	resp.reason = strings::dup(reason);
 };
diff --git a/net/http/error.ha b/net/http/error.ha
index 9a5bf26..d529bf3 100644
--- a/net/http/error.ha
+++ b/net/http/error.ha
@@ -4,7 +4,11 @@ use net::dial;
 // Errors possible while servicing HTTP requests. Note that these errors are for
 // errors related to the processing of the HTTP connection; semantic HTTP errors
 // such as [[STATUS_NOTFOUND]] are not handled by this type.
-export type error = !(dial::error | io::error);
+export type error = !(dial::error | io::error | protoerr);
+
+// An HTTP protocol error occurred, indicating that the remote party is not
+// conformant with HTTP semantics.
+export type protoerr = void;
 
 // Converts an [[error]] to a string.
 export fn strerror(err: error) const str = {
@@ -13,5 +17,7 @@ export fn strerror(err: error) const str = {
 		return dial::strerror(err);
 	case let err: io::error =>
 		return io::strerror(err);
+	case protoerr =>
+		return "HTTP protocol error";
 	};
 };
diff --git a/net/http/header.ha b/net/http/header.ha
index ef5e8ff..53c416c 100644
--- a/net/http/header.ha
+++ b/net/http/header.ha
@@ -64,7 +64,7 @@ export fn write_header(sink: io::handle, head: *header) (size | io::error) = {
 	return z;
 };
 
-fn read_header(head: *header, scan: *bufio::scanner) (void | io::error) = {
+fn read_header(head: *header, scan: *bufio::scanner) (void | error) = {
 	for (true) {
 		const item = match (bufio::scan_string(scan, "\r\n")) {
 		case let line: const str =>
@@ -74,15 +74,19 @@ fn read_header(head: *header, scan: *bufio::scanner) (void | io::error) = {
 		case let err: io::error =>
 			return err;
 		case utf8::invalid =>
-			abort(); // TODO
+			return protoerr;
 		};
 		if (item == "") {
 			break;
 		};
 
-		// TODO: validate field-name
 		let (name, val) = strings::cut(item, ":");
 		val = strings::trim(val);
+		if (val == "") {
+			return protoerr;
+		};
+		// TODO: validate field-name
+
 		header_add(head, name, val);
 	};
 };