@@ -358,6 +358,11 @@ def _validate_rrsig(
     if policy is None:
         policy = default_policy
 
+    # RFC 4035 section 5.3.1: the RRSIG must cover the RRset's type and class.
+    _, rdataset = _get_rrname_rdataset(rrset)
+    if rrsig.type_covered != rdataset.rdtype or rrsig.rdclass != rdataset.rdclass:
+        raise ValidationFailure("RRSIG does not cover the RRset")
+
     candidate_keys = _find_candidate_keys(keys, rrsig)
     if candidate_keys is None:
         raise ValidationFailure("unknown key")
 
@@ -6,6 +6,12 @@ What's New in dnspython
 2.9.1 (in development)
 ----------------------
 
+* DNSSEC validation now rejects an RRSIG whose type covered or class does not
+  match the RRset, as RFC 4035 section 5.3.1 requires.  This was not checked,
+  so a revoked DNSKEY, which may only validate the DNSKEY RRset, still
+  validated any RRset signed with its private key if the RRSIG claimed to
+  cover DNSKEY.
+
 * ``dns.tokenizer.Tokenizer`` now ends a line at a carriage return, or at a
   carriage return followed by a line feed, unless the carriage return is in a
   quoted string.  The carriage return of CRLF line ends used to stay in the
 
@@ -1168,6 +1168,34 @@ def testRevokedKeyOnlyValidatesDNSKEY(self):
         with self.assertRaises(dns.dnssec.ValidationFailure):
             dns.dnssec.validate(a_rrset, dns.rrset.from_rdata(signer, 300, rrsig), keys)
 
+    def testRRSIGMustCoverRRsetType(self):
+        # RFC 4035 section 5.3.1: the RRSIG type covered and class must match
+        # the RRset.  Otherwise a revoked key could sign any RRset with an
+        # RRSIG claiming to cover DNSKEY.
+        private_key = ed25519.Ed25519PrivateKey.generate()
+        dnskey = dns.dnssec.make_dnskey(
+            public_key=private_key.public_key(),
+            algorithm=dns.dnssec.Algorithm.ED25519,
+            flags=Flag.ZONE | Flag.SEP | Flag.REVOKE,
+        )
+        signer = dns.name.from_text("example")
+        keys = {signer: dns.rrset.from_rdata(signer, 300, dnskey)}
+        a_rrset = dns.rrset.from_text(signer, 300, "IN", "A", "10.0.0.1")
+        rrsig = dns.dnssec.sign(a_rrset, private_key, signer, dnskey, lifetime=300)
+        rrsig = rrsig.replace(type_covered=dns.rdatatype.DNSKEY)
+        data = dns.dnssec._make_rrsig_signature_data(a_rrset, rrsig)
+        rrsig = rrsig.replace(signature=private_key.sign(data))
+        with self.assertRaises(dns.dnssec.ValidationFailure):
+            dns.dnssec.validate(a_rrset, dns.rrset.from_rdata(signer, 300, rrsig), keys)
+
+        txt_rrset = dns.rrset.from_text(signer, 300, "IN", "TXT", "foo")
+        rrsig = dns.dnssec.sign(txt_rrset, private_key, signer, dnskey, lifetime=300)
+        ch_rrset = dns.rrset.from_text(signer, 300, "CH", "TXT", "foo")
+        with self.assertRaises(dns.dnssec.ValidationFailure):
+            dns.dnssec.validate(
+                ch_rrset, dns.rrset.from_rdata(signer, 300, rrsig), keys
+            )
+
 
 @unittest.skipUnless(dns.dnssec._have_pyca, "Python Cryptography cannot be imported")
 class DNSSECMiscTestCase(unittest.TestCase):