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Fencer Vulns
high 7.5

CVE-2026-56862 json

Limit handshake messages we are willing to accept post-handshake in crypto/tls

published 2026-08-13 2 mo ago modified 2026-10-24 16 d ago also BIT-golang-2026-56862 , EUVD-2026-58511 , GO-2026-6090

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

Handshake messages, such as KeyUpdate, are always considered as state-advancing, regardless of whether a handshake has been completed or not. As a result, a malicious client can keep sending KeyUpdate messages to force the server to keep performing key derivation operations indefinitely.

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 crypto/tls 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-2026-56862

  • golang-1.22 Ubuntu 22.04 LTS 1.22.2-2~22.04.4
  • golang-1.22 Ubuntu 24.04 LTS 1.22.2-2ubuntu0.5

ubuntu advisories UBUNTU-CVE-2026-56862

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • microshift openshift 4.16 4.16.73-202610151747.p0.g44abd51.assembly.4.16.73.el9
  • microshift-olm openshift 4.16 4.16.73-202610151747.p0.g44abd51.assembly.4.16.73.el9
  • microshift-multus openshift 4.16 4.16.73-202610151747.p0.g44abd51.assembly.4.16.73.el9
  • microshift-selinux openshift 4.16 4.16.73-202610151747.p0.g44abd51.assembly.4.16.73.el9
  • microshift-greenboot openshift 4.16 4.16.73-202610151747.p0.g44abd51.assembly.4.16.73.el9
  • microshift-networking openshift 4.16 4.16.73-202610151747.p0.g44abd51.assembly.4.16.73.el9
  • microshift-release-info openshift 4.16 4.16.73-202610151747.p0.g44abd51.assembly.4.16.73.el9
  • microshift-olm-release-info openshift 4.16 4.16.73-202610151747.p0.g44abd51.assembly.4.16.73.el9

red hat advisories RHSA-2026:83631RHSA-2026:80167RHSA-2026:74797RHSA-2026:73864RHSA-2026:76795RHSA-2026:76809

  • 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
  • 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
  • go1.27 openSUSE Tumbleweed 1.27rc3-1.1

opensuse advisories openSUSE-SU-2026:21999-1openSUSE-SU-2026:11727-1openSUSE-SU-2026:21761-1openSUSE-SU-2026:21705-1openSUSE-SU-2026:21696-1openSUSE-SU-2026:21593-1

  • 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
  • podman-remote AlmaLinux 9 6:5.8.2-7.el9_8

almalinux advisories ALSA-2026:70640ALSA-2026:70641ALSA-2026:69961ALSA-2026:70201ALSA-2026:70391ALSA-2026:69308

  • 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
  • yggdrasil Rocky Linux 10 0.4.9.2-1.el10_2.3
  • git-lfs Rocky Linux 8 3.4.1-13.el8_10
  • git-lfs Rocky Linux 9 3.7.1-4.el9_8.3

rocky linux advisories RLSA-2026:70640RLSA-2026:70641RLSA-2026:70201RLSA-2026:69961RLSA-2026:70391RLSA-2026:69308

  • go Alpine 3.24 1.26.8-r0

alpine advisories ALPINE-CVE-2026-56862

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-2026-56862 updated cvss 7.5

crypto/tls: golang: Golang crypto/tls: Denial of Service via indefinite KeyUpdate messages

  • 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 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-tech-preview/agent-client-rhel9, exploit-intelligence-tech-preview/vulnerability-analysis-rhel9, exploit-intelligence-tech-preview/exploit-intelligence-operator-controller-rhel9 Red Hat ExternalDNS Operator edo/external-dns-rhel9, edo/external-dns-rhel9-operator
    +14 more products
    Red Hat Fence Agents Remediation Operator workload-availability/fence-agents-remediation-rhel8-operator Red Hat Logical Volume Manager Storage lvms4/topolvm-rhel8, lvms4/topolvm-rhel9 Red Hat Machine Deletion Remediation Operator workload-availability/machine-deletion-remediation-rhel8-operator Red Hat mirror registry for Red Hat OpenShift 2 openshift/mirror-registry-rhel8 Red Hat Multicluster Engine for Kubernetes multicluster-engine/hive-rhel9, multicluster-engine/maestro-rhel9, multicluster-engine/assisted-service-9-rhel9, multicluster-engine/clusterclaims-controller-rhel9, multicluster-engine/cluster-curator-controller-rhel9, multicluster-engine/cluster-image-set-controller-rhel9, +2 more 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 Red Hat 3scale API Management Platform 2 3scale-amp2/3scale-operator-bundle
    affected: no fix available
  • 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 4.11.5-1.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
    affected: no fix available “Fix deferred”
  • Red Hat Ceph Storage 7 thrift, rhceph/grafana-rhel9
    affected: no fix available, no fix planned “Out of support scope”
  • Red Hat Ceph Storage 8 thrift, libarrow, thrift-qt, perl-thrift, thrift-glib, parquet-libs, +8 more
    affected: no fix available “Fix deferred”
  • Red Hat Ceph Storage 9 thrift, libarrow, parquet-libs, rhceph/alloy-rhel10
    affected: no fix available, no fix planned “Out of support scope”
show 6 more
  • 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 7 rhc Red Hat Enterprise Linux 9 runc, delve, butane, ignition, ignition-edge, ignition-grub, +8 more
    affected: no fix available
  • Red Hat Enterprise Linux 10 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, gvisor-tap-vsock 0.8.7-1.el10
    affected: no fix available, no fix planned “Will not fix”
  • 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-kueue-controller-rhel9, rhoai/odh-ml-pipelines-driver-rhel9, rhoai/odh-ml-pipelines-launcher-rhel9, rhoai/odh-llm-d-batch-gateway-gc-rhel9, rhoai/odh-rhaii-cluster-validator-rhel9, +13 more Red Hat OpenShift Cluster Manager CLI ocm-cli-clients/ocm-cli-rhel9
    affected: no fix available
  • Red Hat OpenShift Container Platform 4 runc, butane, podman, skopeo, ignition, podman-tests, +16 more Red Hat OpenShift Container Platform 5 openshift5/frr-rhel9, cri-tools 1.35.0-2.el9, 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, +3 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”

12 more affected, 129 more fixed, 125 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 crypto/tls

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.