diff --git a/spec/electra/attestation.go b/spec/electra/attestation.go
index ab4589b8..80e3aa6a 100644
--- a/spec/electra/attestation.go
+++ b/spec/electra/attestation.go
@@ -35,7 +35,7 @@ type Attestation struct {
 	Data            *phase0.AttestationData
 	Signature       phase0.BLSSignature `ssz-size:"96"`
 	// bitfield.Bitvector64 is an 8 byte array so dynamic sizing doesn't make sense.
-	CommitteeBits bitfield.Bitvector64 `ssz-size:"64"`
+	CommitteeBits bitfield.Bitvector64 `ssz-size:"8"`
 }
 
 // attestationJSON is a raw representation of the struct.
diff --git a/spec/electra/attestation_ssz.go b/spec/electra/attestation_ssz.go
index 3826bd83..a63a145b 100644
--- a/spec/electra/attestation_ssz.go
+++ b/spec/electra/attestation_ssz.go
@@ -1,6 +1,6 @@
 // Code generated by fastssz. DO NOT EDIT.
-// Hash: 705104a536b16a7da183e694e9343314f84e5534018fb037f4f0dd0e1dfc35ff
-// Version: 0.1.3
+// Hash: b0798a335e098bab2bb8b3e155e205de20254ede6d1833559b6cc13d071a4239
+// Version: 0.1.4
 package electra
 
 import (
@@ -40,8 +40,8 @@ func (a *Attestation) MarshalSSZTo(buf []byte) (dst []byte, err error) {
 	dst = append(dst, a.CommitteeBits...)
 
 	// Field (0) 'AggregationBits'
-	if size := len(a.AggregationBits); size > 16385 {
-		err = ssz.ErrBytesLengthFn("Attestation.AggregationBits", size, 16385)
+	if size := len(a.AggregationBits); size > 131072 {
+		err = ssz.ErrBytesLengthFn("Attestation.AggregationBits", size, 131072)
 		return
 	}
 	dst = append(dst, a.AggregationBits...)
@@ -89,7 +89,7 @@ func (a *Attestation) UnmarshalSSZ(buf []byte) error {
 	// Field (0) 'AggregationBits'
 	{
 		buf = tail[o0:]
-		if err = ssz.ValidateBitlist(buf, 16385); err != nil {
+		if err = ssz.ValidateBitlist(buf, 131072); err != nil {
 			return err
 		}
 		if cap(a.AggregationBits) == 0 {
@@ -124,7 +124,7 @@ func (a *Attestation) HashTreeRootWith(hh ssz.HashWalker) (err error) {
 		err = ssz.ErrEmptyBitlist
 		return
 	}
-	hh.PutBitlist(a.AggregationBits, 16385)
+	hh.PutBitlist(a.AggregationBits, 131072)
 
 	// Field (1) 'Data'
 	if a.Data == nil {