CVE-2026-78663
Critical
Description
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.
SeverityCritical
CVSS9.1
Exploit probability—
Product
Stdlib
PublishedOct 8, 2026
First seenOct 8, 2026
Weakness typeCWE-675CWE-675
How to fix
Update
- stdlib1.26.9, 1.27.2 or later
- golang.org/x/net0.60.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| stdlibGo | v < 1.26.9, 1.27.0-0 ≤ v < 1.27.2 | 1.26.9, 1.27.2 |
| golang.org/x/netGo | v < 0.60.0 | 0.60.0 |
| microsoft azl3_cert-manager_1.12.15-14 | No range specified | — |
| microsoft azl3_cloud-provider-kubevirt_0.5.1-9 | No range specified | — |
| microsoft azl3_containerized-data-importer_1.62.0-8 | No range specified | — |
| microsoft azl3_etcd_3.5.33-1 | No range specified | — |
| microsoft azl3_influxdb_2.7.5-21 | No range specified | — |
| microsoft azl3_kata-containers_4.1.0.kata0-1 | No range specified | — |
| microsoft azl3_kata-containers-cc_3.15.0.aks0-21 | No range specified | — |
| microsoft azl3_keda_2.14.1-19 | No range specified | — |
| microsoft azl3_kube-vip-cloud-provider_0.0.10-10 | No range specified | — |
| microsoft azl3_kubernetes_1.30.10-30 | No range specified | — |
| microsoft azl3_kubevirt_1.8.4-2 | No range specified | — |
| microsoft azl3_moby-containerd-cc_1.7.7-17 | No range specified | — |
| microsoft azl3_moby-engine_25.0.3-20 | No range specified | — |
| microsoft azl3_opa_0.63.0-5 | No range specified | — |
| microsoft azl3_prometheus-adapter_0.12.0-10 | No range specified | — |
| microsoft azl3_prometheus-node-exporter_1.7.0-5 | No range specified | — |
| microsoft azl3_prometheus-process-exporter_0.8.2-5 | No range specified | — |
| microsoft azl3_golang_1.26.7-1 | No range specified | — |
| microsoft azl3_golang_1.27.1-1 | No range specified | — |
| microsoft azl3_kata-containers_4.1.0.kata1-2 | No range specified | — |
| microsoft azl3_kata-containers-cc_3.15.0.aks0-23 | No range specified | — |
| microsoft azl3_kubernetes_1.30.10-32 | No range specified | — |
| microsoft azl3_moby-containerd-cc_1.7.7-19 | No range specified | — |
| microsoft azl3_moby-engine_25.0.18-1 | No range specified | — |
| microsoft azl3_golang_1.26.10-1 | No range specified | — |
| microsoft azl3_golang_1.27.3-1 | No range specified | — |
| microsoft azl3_kubevirt-openvmm_1.9.0-1 | No range specified | — |
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