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Fencer Vulns
high 7.5

CVE-2026-56853 json

Apply ReadHeaderTimeout when doing unencrypted HTTP/2 check in net/http

published 2026-08-13 2 mo ago modified 2026-10-07 33 d ago also BIT-golang-2026-56853 , EUVD-2026-58510 , GO-2026-6089

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being applied when doing this.

Patch / fix

  • bitnami golang 1.25.13, 1.26.6, 1.27.0
  • go stdlib 1.25.13, 1.26.6, 1.27.0-rc.3
  • Go standard library net/http 1.25.13, 1.26.6, 1.27.0-rc.3
  • golang-1.26 Debian 14 1.26.6-1
  • golang-1.27 Debian 14 1.27~rc3-1

debian advisories DEBIAN-CVE-2026-56853

  • foreman satellite utils 6.17, satellite capsule 6.17, satellite 6.17 3.14.0.22-1.el9sat
  • satellite satellite utils 6.17, satellite capsule 6.17, satellite 6.17 6.17.12-1.el9sat
  • foreman-cli satellite utils 6.17, satellite 6.17 3.14.0.22-1.el9sat
  • foreman-ec2 satellite 6.17 3.14.0.22-1.el9sat
  • foreman-pcp satellite capsule 6.17, satellite 6.17 3.14.0.22-1.el9sat
  • python-lxml satellite capsule 6.17, satellite 6.17 5.3.1-2.el9pc
  • foreman-ovirt satellite 6.17 3.14.0.22-1.el9sat
  • foreman-redis satellite 6.17 3.14.0.22-1.el9sat

red hat advisories RHSA-2026:76795RHSA-2026:76809RHSA-2026:74505RHSA-2026:74504RHSA-2026:74506RHSA-2026:71672

  • govulncheck-vulndb SLES for SAP applications 16.0, SLES 16.0 0.0.20260827T195228-160000.1.1
  • go1.26-openssl SLES for SAP applications 16.0, SLES 16.0 1.26.7-160000.1.1
  • go1.25-openssl SLES for SAP applications 16.0, SLES 16.0 1.25.14-160000.1.1
  • go1.27 SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 1.27.0-150000.1.6.1
  • go1.26-openssl SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Development Tools 15 SP7 1.26.7-150600.13.15.1
  • go1.25-openssl SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Development Tools 15 SP7 1.25.14-150600.13.27.1
  • go1.25-openssl SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 1.25.14-150000.1.33.1
  • go1.26-openssl SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 1.26.7-150000.1.18.1

suse advisories SUSE-SU-2026:23625-1SUSE-SU-2026:23576-1SUSE-SU-2026:23573-1SUSE-SU-2026:3830-1SUSE-SU-2026:3816-1SUSE-SU-2026:3815-1

  • rclone openSUSE Leap 16.0 1.75.1-bp160.1.1
  • kyverno openSUSE Tumbleweed 1.19.1-1.1
  • rclone openSUSE Tumbleweed 1.75.1-1.1
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260827T195228-160000.1.1
  • go1.26-openssl openSUSE Leap 16.0 1.26.7-160000.1.1
  • go1.25-openssl openSUSE Leap 16.0 1.25.14-160000.1.1
  • go1.26 openSUSE Leap 16.0 1.26.6-160000.1.1
  • go1.25 openSUSE Leap 16.0 1.25.13-160000.1.1

opensuse advisories openSUSE-SU-2026:21999-1openSUSE-SU-2026:11822-1openSUSE-SU-2026:11727-1openSUSE-SU-2026:21761-1openSUSE-SU-2026:21705-1openSUSE-SU-2026:21696-1

  • oci-seccomp-bpf-hook AlmaLinux 10 1.2.11-3.el10_2
  • buildah AlmaLinux 9 2:1.43.3-2.el9_8
  • buildah-tests AlmaLinux 9 2:1.43.3-2.el9_8
  • skopeo AlmaLinux 9 2:1.22.2-8.el9_8
  • skopeo-tests AlmaLinux 9 2:1.22.2-8.el9_8
  • podman AlmaLinux 9 6:5.8.2-7.el9_8
  • podman-tests AlmaLinux 9 6:5.8.2-7.el9_8
  • podman-docker AlmaLinux 9 6:5.8.2-7.el9_8

almalinux advisories ALSA-2026:89752ALSA-2026:70640ALSA-2026:70641ALSA-2026:69961ALSA-2026:70201ALSA-2026:70391

  • oci-seccomp-bpf-hook Rocky Linux 10 1.2.11-3.el10_2
  • buildah Rocky Linux 9 2:1.43.3-2.el9_8
  • skopeo Rocky Linux 9 2:1.22.2-8.el9_8
  • podman Rocky Linux 10 7:5.8.2-9.el10_2
  • podman Rocky Linux 9 6:5.8.2-7.el9_8
  • containernetworking-plugins Rocky Linux 9 1:1.9.0-4.el9_8
  • osbuild-composer Rocky Linux 8 101.5-2.el8_10.rocky.0.6
  • osbuild-composer Rocky Linux 10 165.1-3.el10_2.2.rocky.0.1

rocky linux advisories RLSA-2026:89752RLSA-2026:70640RLSA-2026:70641RLSA-2026:70201RLSA-2026:69961RLSA-2026:70391

  • go Alpine 3.24 1.26.8-r0

alpine advisories ALPINE-CVE-2026-56853

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-56853 updated cvss 7.5

net/http: golang: Go net/http: Unencrypted HTTP/2 connections vulnerable to Denial of Service

  • Red Hat Assisted Installer for Red Hat OpenShift Container Platform 2 rhai/assisted-installer-rhel9 Red Hat AWS Load Balancer Operator albo/aws-load-balancer-operator Red Hat cert-manager Operator for Red Hat OpenShift cert-manager/cert-manager-operator-rhel9, cert-manager/jetstack-cert-manager-rhel9 Red Hat Confidential Compute Attestation build-of-trustee/trustee-rhel9-operator Red Hat Deployment Validation Operator dvo/deployment-validation-rhel8-operator Red Hat Exploit Intelligence exploit-intelligence/agent-client-rhel9, exploit-intelligence-tech-preview/vulnerability-analysis-rhel9, exploit-intelligence/exploit-intelligence-operator-controller-rhel9
    +12 more products
    Red Hat ExternalDNS Operator edo/external-dns-rhel9, edo/external-dns-rhel9-operator Red Hat Fence Agents Remediation Operator workload-availability/fence-agents-remediation-rhel8-operator Red Hat Machine Deletion Remediation Operator workload-availability/machine-deletion-remediation-rhel8-operator Red Hat Multicluster Engine for Kubernetes multicluster-engine/hive-rhel9, multicluster-engine/maestro-rhel9, multicluster-engine/assisted-service-9-rhel9, multicluster-engine/kube-rbac-proxy-mce-rhel9, multicluster-engine/managedcluster-import-controller-rhel9 Red Hat Node HealthCheck Operator workload-availability/node-healthcheck-rhel8-operator, workload-availability/node-healthcheck-operator-bundle Red Hat Node Maintenance Operator workload-availability/node-maintenance-operator-bundle Red Hat OpenShift Developer Tools and Services helm 3.11.1-6.el8 Red Hat OpenShift Lightspeed openshift-lightspeed/otelcol-lightspeed-rhel9 Red Hat OpenShift Pipelines openshift-pipelines-client 1.22.0-11814.el9, openshift-pipelines/pipelines-scheduler-rhel9 Red Hat OpenShift Serverless kn-workflow-plugin 1.38.0-3.el9, openshift-serverless-clients 1.17.0-4.el9, openshift-serverless-1/kn-plugin-event-sender-rhel9 Red Hat OpenShift Service Mesh 3 openshift-golang-builder-container Red Hat Power monitoring for Red Hat OpenShift openshift-power-monitoring/kepler-rhel9
    affected: no fix available
  • Red Hat 3scale API Management Platform 2 3scale-amp2/3scale-operator-bundle
    affected: no fix planned “Will not fix”
  • Red Hat Advanced Cluster Management for Kubernetes 2 flightctl-agent, flightctl-selinux, rhacm2/subctl-rhel9, flightctl 0.10.0-1.el9em
    affected: no fix available, no fix planned “Will not fix”
  • Red Hat AI Inference Server rhaiis/vllm-cpu-rhel9, rhaiis/vllm-tpu-rhel9
    affected: no fix planned “Will not fix”
  • Red Hat Ansible Automation Platform 2 python3.11-galaxy-ng 4.10.11-2.el9ap, ansible-automation-platform-27/receptor-rhel9
    affected: no fix available, no fix planned “Will not fix”
  • Red Hat Ceph Storage 5 rhceph/snmp-notifier-rhel8 Red Hat Ceph Storage 6 rhceph/snmp-notifier-rhel9 Red Hat Ceph Storage 7 rhceph/grafana-rhel9 Red Hat Ceph Storage 8 thrift, libarrow, thrift-qt, perl-thrift, thrift-glib, parquet-libs, +8 more Red Hat Ceph Storage 9 thrift, libarrow, parquet-libs, rhceph/alloy-rhel10
    affected: no fix available “Fix deferred”
  • Red Hat Certification Program for Red Hat Enterprise Linux 9 redhat-certification-cnf 9.0-20240522.1.el9, redhat-certification-preflight 9.37-20260618.el9 Red Hat Connectivity Link 1 rhcl-1/coredns-rhel9 Red Hat Enterprise Linux 8 git-lfs, git-lfs 3.7.1-5.el10_2.7
    affected: no fix available
  • Red Hat Enterprise Linux 9 rhc, delve, butane, git-lfs, ignition, grafana-pcp, +13 more Red Hat Enterprise Linux 10 rhc 0.3.13-1.el10_3, delve 1.26.1-2.el10_2, butane 0.27.0-1.el10_2, ignition 2.27.0-2.el10, oci-delta 0.3.0-1.el10, yggdrasil 0.4.10-1.el10, +2 more
    affected: no fix available, no fix planned “Will not fix”
show 5 more
  • Red Hat Enterprise Linux AI (RHEL AI) 3 golang 1.25.1-1.el9 Red Hat OpenShift AI (RHOAI) rhoai/odh-dashboard-rhel9, rhoai/odh-model-registry-rhel9, rhoai/odh-kueue-controller-rhel9, rhoai/odh-ml-pipelines-driver-rhel9, rhoai/odh-ml-pipelines-launcher-rhel9, rhoai/odh-llm-d-batch-gateway-gc-rhel9, +15 more Red Hat OpenShift Cluster Manager CLI ocm-cli-clients/ocm-cli-rhel9
    affected: no fix available
  • Red Hat OpenShift Container Platform 4 podman, skopeo, ignition, cri-tools, podman-tests, skopeo-tests, +12 more Red Hat OpenShift Container Platform 5 cri-tools, ose-crio-credential-provider, openshift5/ose-kube-rbac-proxy-rhel9, cri-o 1.35.5-3.rhaos4.22.git0adf62b.el9, openshift 4.22.0-202608010430.p2.g5f1e0e7.assembly.stream.el9, openshift-clients 4.22.0-202607132126.p2.g7ec2e14.assembly.stream.el9, +2 more
    affected: no fix available, no fix planned “Will not fix”
  • Red Hat OpenShift for Windows Containers openshift4-wincw/windows-machine-config-rhel9-operator
    affected: no fix available
  • Red Hat OpenShift GitOps openshift-gitops-1/dex-rhel8, microshift-gitops 1.19.2-36.el9
    affected: no fix available, no fix planned “Will not fix”
  • Red Hat OpenShift on AWS rosa 1.2.64-b2f7c89.el8
    affected: no fix available

8 more affected, 98 more fixed, 99 more not affected in the full advisory

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.57% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami golang
<1.25.13
>=1.26.0-0, <1.26.6
>=1.27.0-0, <1.27.0
1.25.13
1.26.6
1.27.0
go stdlib
<1.25.13
>=1.26.0-0, <1.26.6
>=1.27.0-0, <1.27.0-rc.3
1.25.13
1.26.6
1.27.0-rc.3

Affected products

  • Go standard library net/http

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.