diff --git a/gen/internal_test.go b/gen/internal_test.go
index 398322e..e0bc31e 100644
--- a/gen/internal_test.go
+++ b/gen/internal_test.go
@@ -114,6 +114,29 @@ func TestCoerceScalarArrayTable(t *testing.T) {
 	}
 }
 
+func TestParseSecurityReqTable(t *testing.T) {
+	cases := []struct {
+		want map[string][]string
+		in   string
+	}{
+		{map[string][]string{"ApiKeyAuth": nil}, "ApiKeyAuth"},
+		{map[string][]string{"OAuth2Application": {"write", "admin"}}, "OAuth2Application[write, admin]"},
+		// && combines schemes into a single requirement (all required together)
+		{map[string][]string{"ApiKeyAuth": nil, "BearerAuth": nil}, "ApiKeyAuth && BearerAuth"},
+		{map[string][]string{"OAuth2Application": {"write"}, "ApiKeyAuth": nil}, "OAuth2Application[write] && ApiKeyAuth"},
+		{map[string][]string{"A": nil, "B": nil}, "  A  &&  B  "}, // whitespace tolerated
+		{map[string][]string{"A": nil}, "A && "},                  // empty part skipped
+		{nil, "[write]"},                                          // malformed: missing scheme name
+		{nil, ""},                                                 // no schemes: nil, never {} ("no auth")
+		{nil, " && "},                                             // separators only: nil as well
+	}
+	for _, c := range cases {
+		if got := parseSecurityReq(c.in); !reflect.DeepEqual(got, c.want) {
+			t.Errorf("parseSecurityReq(%q) = %#v, want %#v", c.in, got, c.want)
+		}
+	}
+}
+
 func TestApplyValidationRulesTable(t *testing.T) {
 	str := &Schema{Type: []string{"string"}}
 	applyValidationRules(str, "min=3,max=10,len=4")
@@ -160,6 +183,33 @@ func TestApplyValidationRulesTable(t *testing.T) {
 	applyValidationRules(nil, "min=1")
 }
 
+func TestMalformedSecurityEmitsNoRequirement(t *testing.T) {
+	// A nil/empty parse result must not be appended: a {} requirement would
+	// mean "no auth required". Guards live in applySecurity and parseOperation.
+	api := &API{SecuritySchemes: map[string]SecurityScheme{}, Extensions: map[string]any{}}
+	parseGeneral(parseCommentGroup(`@title T
+@securitydefinitions.apikey K
+@in header
+@name Authorization
+@security [write]
+@security K`), api)
+	if len(api.Security) != 1 {
+		t.Fatalf("document security must keep only the valid requirement: %#v", api.Security)
+	}
+	if _, ok := api.Security[0]["K"]; !ok || len(api.Security[0]) != 1 {
+		t.Fatalf("document security requirement must reference exactly scheme K: %#v", api.Security[0])
+	}
+
+	res := &resolver{src: &source{}, schemas: map[string]*Schema{}}
+	op := parseOperation(parseCommentGroup(`@Router /x [get]
+@Summary X
+@Security [write]
+@Security K`), res, refCtx{})
+	if len(op.Security) != 1 {
+		t.Fatalf("operation security must keep only the valid requirement: %#v", op.Security)
+	}
+}
+
 func TestSchemeContextEndsAtNonSecurityDirective(t *testing.T) {
 	api := &API{SecuritySchemes: map[string]SecurityScheme{}, Extensions: map[string]any{}}
 	parseGeneral(parseCommentGroup(`@title T
diff --git a/gen/parse.go b/gen/parse.go
index 657d7a4..f95a686 100644
--- a/gen/parse.go
+++ b/gen/parse.go
@@ -207,7 +207,9 @@ func (p *generalParser) applySecurity(d directive) bool {
 	case d.name == "security":
 		// document-level security requirement — not a scheme attribute, so
 		// it ends the scheme section like any other non-scheme directive
-		p.api.Security = append(p.api.Security, parseSecurityReq(d.args))
+		if req := parseSecurityReq(d.args); len(req) > 0 {
+			p.api.Security = append(p.api.Security, req)
+		}
 		p.lastScheme = nil
 	case p.lastScheme == nil:
 		return false
@@ -295,7 +297,9 @@ func parseOperation(ds []directive, res *resolver, ctx refCtx) Operation {
 		case "success", "failure", "response":
 			op.Responses = append(op.Responses, parseResponses(d.args, res, ctx)...)
 		case "security":
-			op.Security = append(op.Security, parseSecurityReq(d.args))
+			if req := parseSecurityReq(d.args); len(req) > 0 {
+				op.Security = append(op.Security, req)
+			}
 		case "header":
 			attachHeader(&op, d.args)
 		case "externaldocs.url":
@@ -401,19 +405,34 @@ func splitMimeList(args string) []string {
 
 func parseSecurityReq(args string) map[string][]string {
 	req := map[string][]string{}
-	// "OAuth2Application[write, admin]" or "ApiKeyAuth"
-	name := args
-	var scopes []string
-	if open := strings.IndexByte(args, '['); open >= 0 {
-		name = strings.TrimSpace(args[:open])
-		inner := strings.Trim(args[open:], "[] ")
-		for s := range strings.SplitSeq(inner, ",") {
-			if s = strings.TrimSpace(s); s != "" {
-				scopes = append(scopes, s)
+	// One or more schemes combined with && (all required together, swag syntax):
+	// "OAuth2Application[write, admin]", "ApiKeyAuth" or "ApiKeyAuth && BearerAuth".
+	for part := range strings.SplitSeq(args, "&&") {
+		part = strings.TrimSpace(part)
+		if part == "" {
+			continue
+		}
+		name := part
+		var scopes []string
+		if open := strings.IndexByte(part, '['); open >= 0 {
+			name = strings.TrimSpace(part[:open])
+			inner := strings.Trim(part[open:], "[] ")
+			for s := range strings.SplitSeq(inner, ",") {
+				if s = strings.TrimSpace(s); s != "" {
+					scopes = append(scopes, s)
+				}
 			}
 		}
+		if name == "" {
+			continue // malformed scope-only part like "[write]" - no scheme to require
+		}
+		req[name] = scopes
+	}
+	if len(req) == 0 {
+		// An empty Security Requirement Object ({}) would mean "no auth
+		// required" - never emit one for a malformed annotation.
+		return nil
 	}
-	req[name] = scopes
 	return req
 }