diff --git a/.changeset/warm-signatures-smile.md b/.changeset/warm-signatures-smile.md
new file mode 100644
index 00000000..b30bcd60
--- /dev/null
+++ b/.changeset/warm-signatures-smile.md
@@ -0,0 +1,5 @@
+---
+'@bitauth/libauth': patch
+---
+
+Fix `isValidSignatureEncodingDER` to accept valid 8- and 72-byte DER signatures
diff --git a/src/lib/vm/instruction-sets/common/encoding.spec.ts b/src/lib/vm/instruction-sets/common/encoding.spec.ts
new file mode 100644
index 00000000..d33f8b4f
--- /dev/null
+++ b/src/lib/vm/instruction-sets/common/encoding.spec.ts
@@ -0,0 +1,36 @@
+import test from 'ava';
+
+import { isValidSignatureEncodingDER, range } from '../../../lib.js';
+
+const minimumLengthSignature = Uint8Array.from([
+  0x30, 0x06, 0x02, 0x01, 0x01, 0x02, 0x01, 0x01,
+]);
+const maximumLengthInteger = [0, ...range(32).map(() => 0x80)];
+const maximumLengthSignature = Uint8Array.from([
+  0x30,
+  0x46,
+  0x02,
+  0x21,
+  ...maximumLengthInteger,
+  0x02,
+  0x21,
+  ...maximumLengthInteger,
+]);
+const oversizedInteger = [0, ...range(33).map(() => 0x80)];
+const oversizedSignature = Uint8Array.from([
+  0x30,
+  0x47,
+  0x02,
+  0x22,
+  ...oversizedInteger,
+  0x02,
+  0x21,
+  ...maximumLengthInteger,
+]);
+
+test('isValidSignatureEncodingDER: length boundaries', (t) => {
+  t.false(isValidSignatureEncodingDER(minimumLengthSignature.slice(0, -1)));
+  t.true(isValidSignatureEncodingDER(minimumLengthSignature));
+  t.true(isValidSignatureEncodingDER(maximumLengthSignature));
+  t.false(isValidSignatureEncodingDER(oversizedSignature));
+});
diff --git a/src/lib/vm/instruction-sets/common/encoding.ts b/src/lib/vm/instruction-sets/common/encoding.ts
index cac63230..2c0d344d 100644
--- a/src/lib/vm/instruction-sets/common/encoding.ts
+++ b/src/lib/vm/instruction-sets/common/encoding.ts
@@ -86,8 +86,8 @@ const isValidInteger = (
 // eslint-disable-next-line complexity
 export const isValidSignatureEncodingDER = (signature: Uint8Array) => {
   const correctLengthRange =
-    signature.length > DER.minimumLength &&
-    signature.length < DER.maximumLength;
+    signature.length >= DER.minimumLength &&
+    signature.length <= DER.maximumLength;
   const correctSequenceTagType =
     signature[DER.sequenceTagIndex] === ASN1.sequenceTagType;
   const correctSequenceLength =