diff --git a/ssh/knownhosts/knownhosts.go b/ssh/knownhosts/knownhosts.go
index e57cf5b..1ef1c35 100644
--- a/ssh/knownhosts/knownhosts.go
+++ b/ssh/knownhosts/knownhosts.go
@@ -178,7 +178,7 @@ func nextWord(line []byte) (string, []byte) {
 		return string(line), nil
 	}
 
-	return string(line[:i]), bytes.TrimSpace(line[i:])
+	return string(line[:i]), trimSpace(line[i:])
 }
 
 func parseLine(line []byte) (marker, host string, key ssh.PublicKey, err error) {
@@ -387,7 +387,7 @@ func (db *hostKeyDB) Read(r io.Reader, filename string) error {
 	for scanner.Scan() {
 		lineNum++
 		line := scanner.Bytes()
-		line = bytes.TrimSpace(line)
+		line = trimSpace(line)
 		if len(line) == 0 || line[0] == '#' {
 			continue
 		}
@@ -535,3 +535,10 @@ func newHashedHost(encoded string) (*hashedHost, error) {
 func (h *hashedHost) match(a addr) bool {
 	return bytes.Equal(hashHost(Normalize(a.String()), h.salt), h.hash)
 }
+
+// trimSpace removes leading and trailing ASCII whitespace (space and tab). It
+// is used instead of bytes.TrimSpace to match OpenSSH behavior, which strictly
+// parses only ASCII space (0x20) and tab (0x09) as whitespace.
+func trimSpace(in []byte) []byte {
+	return bytes.Trim(in, " \t")
+}
diff --git a/ssh/knownhosts/knownhosts_test.go b/ssh/knownhosts/knownhosts_test.go
index 4d3ca59..8e1fba2 100644
--- a/ssh/knownhosts/knownhosts_test.go
+++ b/ssh/knownhosts/knownhosts_test.go
@@ -8,6 +8,7 @@ import (
 	"bytes"
 	"crypto/ed25519"
 	"crypto/rand"
+	"encoding/base64"
 	"fmt"
 	"net"
 	"reflect"
@@ -407,3 +408,41 @@ func TestIssue36126(t *testing.T) {
 		t.Errorf("should have passed the check, got %v", err)
 	}
 }
+
+func TestUnicodeSpace(t *testing.T) {
+	line := fmt.Sprintf("server.org %s  %s", edKey.Type(), base64.StdEncoding.EncodeToString(edKey.Marshal()))
+
+	db := newHostKeyDB()
+	err := db.Read(bytes.NewBufferString(line), "testdb")
+
+	if err == nil {
+		t.Fatal("Read succeeded on line with Unicode space, expected error due to strict ASCII parsing")
+	}
+}
+
+func TestUnicodeSpaceTrimming(t *testing.T) {
+	const unicodeSpace = " "
+	line := fmt.Sprintf("%sserver.org %s", unicodeSpace, edKeyStr)
+
+	db := newHostKeyDB()
+	err := db.Read(bytes.NewBufferString(line), "testdb")
+
+	if err != nil {
+		t.Fatalf("Read failed: %v", err)
+	}
+
+	lines := db.lines
+	if len(lines) != 1 {
+		t.Fatalf("Expected 1 line, got %d", len(lines))
+	}
+
+	cleanAddr := addr{host: "server.org", port: "22"}
+	dirtyAddr := addr{host: unicodeSpace + "server.org", port: "22"}
+
+	if lines[0].match(cleanAddr) {
+		t.Errorf("Matched clean host 'server.org', implying Unicode space was trimmed")
+	}
+	if !lines[0].match(dirtyAddr) {
+		t.Errorf("Did not match dirty host, implying parsing issue")
+	}
+}