CVE-2026-78663: Double flow control refund on HTTP/2 server streams in net/http

Published Oct 8, 2026
·
Updated

Double flow control refund on HTTP/2 server streams in net/http

Other sources

The HTTP/2 server can refund connection-level flow control twice for the same data: Once when a client resets a stream (refunding data for any sent-but-unread portion of the stream), and again when a request handler reads the buffered data. A malicious client can exploit this to bypass the configured connection-level flow control limit (MaxReceiveBufferPerConnection). Total buffered data is still limited by the concurrent stream limit and stream-level flow control.

— NVD

Affected Software

35 affected componentsFixes available
go net/http
All of the following
azurelinux/prometheus-process-exporter<0.8.2-6
0.8.2-6
Microsoft Azure Linux=3.0
All of the following
azurelinux/prometheus-node-exporter<1.7.0-6
1.7.0-6
Microsoft Azure Linux=3.0
All of the following
azurelinux/etcd<3.5.35-1
3.5.35-1
Microsoft Azure Linux=3.0
All of the following
azurelinux/opa<0.63.0-6
0.63.0-6
Microsoft Azure Linux=3.0
All of the following
azurelinux/influxdb<2.7.5-22
2.7.5-22
Microsoft Azure Linux=3.0
All of the following
azurelinux/kubevirt<1.8.4-4
1.8.4-4
Microsoft Azure Linux=3.0
All of the following
azurelinux/prometheus-adapter<0.12.0-12
0.12.0-12
Microsoft Azure Linux=3.0
All of the following
azurelinux/keda<2.14.1-22
2.14.1-22
Microsoft Azure Linux=3.0
All of the following
azurelinux/kube-vip-cloud-provider<0.0.10-11
0.0.10-11
Microsoft Azure Linux=3.0
All of the following
azurelinux/containerized-data-importer<1.62.0-9
1.62.0-9
Microsoft Azure Linux=3.0
All of the following
azurelinux/cloud-provider-kubevirt<0.5.1-10
0.5.1-10
Microsoft Azure Linux=3.0
All of the following
azurelinux/cert-manager<1.12.15-15
1.12.15-15
Microsoft Azure Linux=3.0
All of the following
azurelinux/kubernetes<1.30.10-32
1.30.10-32
Microsoft Azure Linux=3.0
All of the following
azurelinux/kata-containers<4.1.0.kata1-2
4.1.0.kata1-2
Microsoft Azure Linux=3.0
All of the following
azurelinux/moby-containerd-cc<1.7.7-19
1.7.7-19
Microsoft Azure Linux=3.0
All of the following
azurelinux/kata-containers-cc<3.15.0.aks0-23
3.15.0.aks0-23
Microsoft Azure Linux=3.0
alpine/docker<29.9.0-r0
29.9.0-r0
alpine/go<1.26.9-r0
1.26.9-r0

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade azurelinux/prometheus-process-exporter to a version that resolves this vulnerability.

    Fixed in 0.8.2-6
  2. Upgrade

    Upgrade azurelinux/prometheus-node-exporter to a version that resolves this vulnerability.

    Fixed in 1.7.0-6
  3. Upgrade

    Upgrade azurelinux/etcd to a version that resolves this vulnerability.

    Fixed in 3.5.35-1
  4. Upgrade

    Upgrade azurelinux/opa to a version that resolves this vulnerability.

    Fixed in 0.63.0-6
  5. Upgrade

    Upgrade azurelinux/influxdb to a version that resolves this vulnerability.

    Fixed in 2.7.5-22
  6. Upgrade

    Upgrade azurelinux/kubevirt to a version that resolves this vulnerability.

    Fixed in 1.8.4-4
  7. Upgrade

    Upgrade azurelinux/prometheus-adapter to a version that resolves this vulnerability.

    Fixed in 0.12.0-12
  8. Upgrade

    Upgrade azurelinux/keda to a version that resolves this vulnerability.

    Fixed in 2.14.1-22
  9. Upgrade

    Upgrade azurelinux/kube-vip-cloud-provider to a version that resolves this vulnerability.

    Fixed in 0.0.10-11
  10. Upgrade

    Upgrade azurelinux/containerized-data-importer to a version that resolves this vulnerability.

    Fixed in 1.62.0-9
  11. Upgrade

    Upgrade azurelinux/cloud-provider-kubevirt to a version that resolves this vulnerability.

    Fixed in 0.5.1-10
  12. Upgrade

    Upgrade azurelinux/cert-manager to a version that resolves this vulnerability.

    Fixed in 1.12.15-15
  13. Upgrade

    Upgrade azurelinux/kubernetes to a version that resolves this vulnerability.

    Fixed in 1.30.10-32
  14. Upgrade

    Upgrade azurelinux/kata-containers to a version that resolves this vulnerability.

    Fixed in 4.1.0.kata1-2
  15. Upgrade

    Upgrade azurelinux/moby-containerd-cc to a version that resolves this vulnerability.

    Fixed in 1.7.7-19
  16. Upgrade

    Upgrade azurelinux/kata-containers-cc to a version that resolves this vulnerability.

    Fixed in 3.15.0.aks0-23
  17. Upgrade

    Upgrade alpine/docker to a version that resolves this vulnerability.

    Fixed in 29.9.0-r0
  18. Upgrade

    Upgrade alpine/go to a version that resolves this vulnerability.

    Fixed in 1.26.9-r0

Event History

Oct 8, 2026
CVE Published
via MITRE·10:53 PM
Data Sourced
via MITRE·10:53 PM
DescriptionWeakness
Data Sourced
via NVD·11:17 PM
DescriptionSeverityWeakness
Data Sourced
via OSV·11:17 PM
DescriptionSeverityAffected Software
Oct 11, 2026
Data Sourced
via Microsoft·08:47 AM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

Who is exposed to this issue?

HTTP/2 servers using Go's net/http are exposed if they accept malicious client connections. The issue concerns the configured connection-level receive buffer limit, MaxReceiveBufferPerConnection.

2

What does an attacker need to do to exploit it?

An attacker needs to send data on an HTTP/2 stream, reset that stream, and have the request handler read the buffered data. This causes the same sent-but-unread data to be refunded twice at the connection level.

3

Does this allow unlimited server-side buffering?

No. Although the attacker can bypass the connection-level flow-control limit, total buffered data remains constrained by the concurrent stream limit and stream-level flow control.

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