CVE-2026-78659
Description
When "Trailer" headers are sent by a client, the HTTP server internally uses the header values to populate the Request.Trailer map passed to the server handler. Because Request.Trailer is a map, each entry incurs memory overhead. For HTTP/2 servers, a malicious client can exploit this by sending a "Trailer" header that declares a large number of fields, causing the server to allocate a disproportionate amount of memory while bypassing Server.MaxHeaderValueCount and Server.MaxHeaderBytes limits. This exploit is not applicable for HTTP/1 servers, which do not support multiplexing a large number of requests over one TCP connection, and whose Server.MaxHeaderBytes are calculated differently.
How to fix
- 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_application-gateway-kubernetes-ingress_1.7.7-6 | No range specified | — |
| microsoft azl3_azurelinux-image-tools_1.6.0-3 | No range specified | — |
| 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_containerd2_2.3.4-1 | No range specified | — |
| microsoft azl3_containerized-data-importer_1.62.0-8 | No range specified | — |
| microsoft azl3_coredns_1.11.4-21 | No range specified | — |
| microsoft azl3_docker-buildx_0.14.0-17 | No range specified | — |
| microsoft azl3_docker-compose_2.27.0-14 | No range specified | — |
| microsoft azl3_etcd_3.5.33-1 | No range specified | — |
| microsoft azl3_flannel_0.24.2-32 | No range specified | — |
| microsoft azl3_gh_2.101.0-1 | No range specified | — |
| microsoft azl3_git-lfs_3.6.1-6 | No range specified | — |
| microsoft azl3_influxdb_2.7.5-21 | No range specified | — |
| microsoft azl3_jx_3.10.182-5 | 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_kured_1.15.0-6 | 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_multus_4.0.2-11 | No range specified | — |
| microsoft azl3_opa_0.63.0-5 | No range specified | — |
| microsoft azl3_packer_1.9.5-21 | 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_skopeo_1.14.4-13 | No range specified | — |
| microsoft azl3_telegraf_1.31.0-33 | No range specified | — |
| microsoft azl3_vitess_19.0.4-14 | 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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