diff --git a/go.mod b/go.mod
index 0e77766af8..7f28fb24e8 100644
--- a/go.mod
+++ b/go.mod
@@ -24,7 +24,7 @@ require (
 	k8s.io/apimachinery v0.18.8
 	k8s.io/client-go v11.0.1-0.20190805182717-6502b5e7b1b5+incompatible
 	k8s.io/utils v0.0.0-20200603063816-c1c6865ac451
-	knative.dev/eventing v0.17.1-0.20200923213041-af999217845d
+	knative.dev/eventing v0.17.1-0.20200924215940-2dfc34b5fde8
 	knative.dev/pkg v0.0.0-20200922164940-4bf40ad82aab
 	knative.dev/test-infra v0.0.0-20200921012245-37f1a12adbd3
 )
diff --git a/go.sum b/go.sum
index 264cf9a575..ad110e7f09 100644
--- a/go.sum
+++ b/go.sum
@@ -1931,8 +1931,8 @@ k8s.io/utils v0.0.0-20200603063816-c1c6865ac451 h1:v8ud2Up6QK1lNOKFgiIVrZdMg7Mpm
 k8s.io/utils v0.0.0-20200603063816-c1c6865ac451/go.mod h1:jPW/WVKK9YHAvNhRxK0md/EJ228hCsBRufyofKtW8HA=
 knative.dev/caching v0.0.0-20190719140829-2032732871ff/go.mod h1:dHXFU6CGlLlbzaWc32g80cR92iuBSpsslDNBWI8C7eg=
 knative.dev/caching v0.0.0-20200116200605-67bca2c83dfa/go.mod h1:dHXFU6CGlLlbzaWc32g80cR92iuBSpsslDNBWI8C7eg=
-knative.dev/eventing v0.17.1-0.20200923213041-af999217845d h1:eRqzEXGehiQ7jTUR2AmgGjnLaaCmiL3OCzRXGGWVg2k=
-knative.dev/eventing v0.17.1-0.20200923213041-af999217845d/go.mod h1:Rv5V1Sk/XeG6vdEpRu+zDhEUDg2SgbkOJWRNssUyt50=
+knative.dev/eventing v0.17.1-0.20200924215940-2dfc34b5fde8 h1:ifT6VXVtE6ldkNWxSPX5ElZ+oWq0H7UMmOCgrR+s8eA=
+knative.dev/eventing v0.17.1-0.20200924215940-2dfc34b5fde8/go.mod h1:Rv5V1Sk/XeG6vdEpRu+zDhEUDg2SgbkOJWRNssUyt50=
 knative.dev/eventing-contrib v0.6.1-0.20190723221543-5ce18048c08b/go.mod h1:SnXZgSGgMSMLNFTwTnpaOH7hXDzTFtw0J8OmHflNx3g=
 knative.dev/eventing-contrib v0.6.1-0.20190723221543-5ce18048c08b/go.mod h1:SnXZgSGgMSMLNFTwTnpaOH7hXDzTFtw0J8OmHflNx3g=
 knative.dev/eventing-contrib v0.6.1-0.20190723221543-5ce18048c08b/go.mod h1:SnXZgSGgMSMLNFTwTnpaOH7hXDzTFtw0J8OmHflNx3g=
diff --git a/vendor/knative.dev/eventing/pkg/kncloudevents/message_sender.go b/vendor/knative.dev/eventing/pkg/kncloudevents/message_sender.go
index 96506b28ae..b9fc4f70f1 100644
--- a/vendor/knative.dev/eventing/pkg/kncloudevents/message_sender.go
+++ b/vendor/knative.dev/eventing/pkg/kncloudevents/message_sender.go
@@ -165,7 +165,7 @@ func RetryConfigFromDeliverySpec(spec duckv1.DeliverySpec) (RetryConfig, error)
 		switch *spec.BackoffPolicy {
 		case duckv1.BackoffPolicyExponential:
 			retryConfig.Backoff = func(attemptNum int, resp *nethttp.Response) time.Duration {
-				return time.Duration(math.Pow(float64(delayDuration*2), float64(attemptNum)))
+				return delayDuration * time.Duration(math.Exp2(float64(attemptNum)))
 			}
 		case duckv1.BackoffPolicyLinear:
 			retryConfig.Backoff = func(attemptNum int, resp *nethttp.Response) time.Duration {
diff --git a/vendor/modules.txt b/vendor/modules.txt
index b765033b32..dd69deea24 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -1049,7 +1049,7 @@ k8s.io/utils/buffer
 k8s.io/utils/integer
 k8s.io/utils/pointer
 k8s.io/utils/trace
-# knative.dev/eventing v0.17.1-0.20200923213041-af999217845d
+# knative.dev/eventing v0.17.1-0.20200924215940-2dfc34b5fde8
 ## explicit
 knative.dev/eventing/pkg/adapter/v2
 knative.dev/eventing/pkg/adapter/v2/util/crstatusevent