Skip to content
Fencer Vulns
critical 9.1

CVE-2026-78663 json

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

published 2026-10-08 31 d ago modified 2026-10-16 23 d ago also BIT-golang-2026-78663 , EUVD-2026-95427 , GO-2026-6612

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

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.

Patch / fix

  • bitnami golang 1.26.9, 1.27.2
  • go stdlib 1.26.9, 1.27.2
  • go golang.org/x/net 0.60.0
  • Go standard library net/http 1.26.9
  • Go standard library net/http/internal/http2 1.27.2
  • golang.org/x/net golang.org/x/net/http2 0.60.0
  • golang-1.26 Debian 14 1.26.9-1
  • golang-1.27 Debian 14 1.27.2-1
  • golang-golang-x-net Debian 14 1:0.60.0-1

debian advisories DEBIAN-CVE-2026-78663

  • 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-2026-78663

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

  • google-cloud-sap-agent SLES for SAP applications 16.0, SLES 16.0 3.15-160000.5.1
  • google-guest-agent Linux Micro 6.0 20261022.00-159998.1.1
  • google-guest-agent Linux Micro 6.1 20261022.00-slfo.1.1_1.1
  • go1.26-openssl SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 1.26.10-150000.1.21.2
  • go1.26-openssl SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Development Tools 15 SP7 1.26.10-150600.13.18.1
  • go1.26 SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 1.26.10-150000.1.36.1
  • go1.26 SLES for SAP applications 16.0, SLES 16.0 1.26.10-160000.1.1
  • go1.27 SLES for SAP applications 16.0, SLES 16.0 1.27.2-160000.1.1

suse advisories SUSE-SU-2026:24604-1SUSE-SU-2026:24475-1SUSE-SU-2026:24555-1SUSE-SU-2026:4867-1SUSE-SU-2026:4866-1SUSE-SU-2026:4864-1

  • alloy openSUSE Tumbleweed 1.21.3-1.1
  • amazon-ssm-agent openSUSE Tumbleweed 3.3.5708.0-1.1
  • cadvisor openSUSE Leap 16.0 0.60.6-bp160.4.1
  • kubevirt1.9 openSUSE Leap 16.0 1.9.1-160000.1.1
  • cadvisor openSUSE Tumbleweed 0.60.6-5.1
  • helm openSUSE Tumbleweed 4.3.1-3.1
  • distribution openSUSE Tumbleweed 3.1.2-3.1
  • google-guest-agent openSUSE Tumbleweed 20261022.00-1.1

opensuse advisories openSUSE-SU-2026:12446-1openSUSE-SU-2026:12414-1openSUSE-SU-2026:22218-1openSUSE-SU-2026:22180-1openSUSE-SU-2026:12317-1openSUSE-SU-2026:12326-1

  • golang AlmaLinux 10 1.26.10-1.el10_2.alma.1
  • go-toolset AlmaLinux 10 1.26.10-1.el10_2.alma.1
  • golang-bin AlmaLinux 10 1.26.10-1.el10_2.alma.1
  • golang-src AlmaLinux 10 1.26.10-1.el10_2.alma.1
  • golang-misc AlmaLinux 10 1.26.10-1.el10_2.alma.1
  • golang-race AlmaLinux 10 1.26.10-1.el10_2.alma.1
  • golang-tests AlmaLinux 10 1.26.10-1.el10_2.alma.1
  • golang AlmaLinux 9 1.26.10-1.el9_8

almalinux advisories ALSA-2026:86093ALSA-2026:86196ALSA-2026:86203

  • go Alpine 3.24 1.26.9-r0
  • docker Alpine 3.24 29.9.0-r0

alpine advisories ALPINE-CVE-2026-78663

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

  • cert-manager Azure Linux 3.0 1.12.15-15
  • cloud-provider-kubevirt Azure Linux 3.0 0.5.1-10
  • containerized-data-importer Azure Linux 3.0 1.62.0-9
  • etcd Azure Linux 3.0 3.5.35-1
  • influxdb Azure Linux 3.0 2.7.5-22
  • kata-containers Azure Linux 3.0 4.1.0.kata1-2
  • kata-containers-cc Azure Linux 3.0 3.15.0.aks0-23
  • kube-vip-cloud-provider Azure Linux 3.0 0.0.10-11

azure linux advisories AZL-107192AZL-107219AZL-107264AZL-107366AZL-107523AZL-107567

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2026-78663 updated cvss 5.3

net/http: net/http/internal/http2: golang: golang.org/x/net/http2: golang: flow control limit bypass via double refund in HTTP/2 server

  • Red Hat OpenShift Developer Tools and Services helm 3.22.0-90.el9
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat OpenShift Pipelines openshift-pipelines-client 1.15.3-11580.el8 Red Hat OpenShift Serverless kn-workflow-plugin 1.38.1-1.el9, openshift-serverless-clients 1.17.0-4.el9 Red Hat OpenShift Service Mesh 3 istio-proxy-selinux, istio-proxy 1.30.5-1.el9, openshift-golang-builder-container
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Ansible Automation Platform 2 receptor 1.6.8-1.el9ap, automation-gateway-proxy 2.6.17-3.el9ap, automation-gateway-proxy-openssl30 2.6.6-2.el9ap, automation-gateway-proxy-openssl32 2.6.6-2.el9ap
    affected: workaround, no fix available, no fix planned “Out of support scope”
  • Red Hat Ceph Storage 7 thrift Red Hat Ceph Storage 8 thrift, thrift-qt, perl-thrift, thrift-glib, python3-thrift Red Hat Ceph Storage 9 thrift, libarrow, parquet-libs Red Hat Certification Program for Red Hat Enterprise Linux 9 redhat-certification-cnf 9.0-20240522.1.el9, redhat-certification-preflight 9.42-20261005.el10 Red Hat Edge Manager 1 flightctl 1.2.1-1.el9 Red Hat Enterprise Linux 7 rhc, host-metering, rhc-worker-script, rhc 0.3.13-1.el10_3, host-metering-selinux, compat-sap-c++-11 11.1.1-6.el7_9
    +8 more products
    Red Hat Enterprise Linux 8 rhc, crun, runc, conmon, podman, skopeo, +43 more Red Hat Enterprise Linux 9 rhc, delve, butane, conmon, podman, skopeo, +50 more Red Hat Enterprise Linux 10 toolbox 0.3-3.el10, rhc 0.3.13-1.el10_3, butane 0.29.0-1.el10, conmon 2.1.12-4.el10, delve 1.26.1-2.el10_0, podman 5.8.2-9.el10_2, +20 more Red Hat Enterprise Linux AI (RHEL AI) 3 golang 1.25.1-1.el9 Red Hat OpenShift AI (RHOAI) rhoai/odh-core-bff-rhel9, rhoai/odh-mod-arch-maas-rhel9, rhoai/odh-kube-rbac-proxy-rhel9, rhoai/odh-maas-controller-rhel9, rhoai/odh-mlflow-operator-rhel9, rhoai/odh-mod-arch-automl-rhel9, +24 more Red Hat OpenShift Container Platform 4 cri-o, butane, conmon, podman, skopeo, toolbox, +63 more Red Hat OpenShift Container Platform 5 cri-o, conmon-rs, cri-tools, openshift, microshift, kata-containers, +6 more Red Hat OpenShift on AWS rosa 1.2.64-b2f7c89.el8
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenShift Virtualization 4 openshift-golang-builder-container
    affected: workaround, no fix available
  • Red Hat OpenStack Platform 16.2 etcd, golang-github-infrawatch-apputils 0.5-3.git4ffa970.el8ost Red Hat OpenStack Platform 17.1 etcd, golang-uber-multierr, collectd-libpod-stats, golang-uber-atomic 1.5.1-1.el8ost.1, golang-github-infrawatch-apputils 0.5-3.git4ffa970.el8ost
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat OpenStack Platform 18.0 etcd, golang-github-openstack-k8s-operators-os-diff 0.1.1-18.0.20260602234717.a95ae05.el9ost Red Hat Satellite 6 yggdrasil-worker-forwarder 0.1.0-2.1.el9sat
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Service Interconnect 1 skupper-cli 1.8.8-1.el9
    affected: workaround, no fix planned “Out of support scope”
show 15 more
  • Red Hat Service Interconnect 2 skupper-cli 1.8.8-1.el9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat streams for Apache Kafka 2 golang-github-danielqsj-kafka_exporter 1.9.0-12.el9
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat streams for Apache Kafka 3 golang-github-danielqsj-kafka_exporter 1.9.0-12.el9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux AppStream (v. 8) delve 1.26.1-1.module+el8.10.0+24516+40554724, golang 1.26.10-1.module+el8.10.0+25107+6b50279c, go-toolset 1.26.10-1.module+el8.10.0+25107+6b50279c, golang-bin 1.26.10-1.module+el8.10.0+25107+6b50279c, golang-src 1.26.10-1.module+el8.10.0+25107+6b50279c, golang-misc 1.26.10-1.module+el8.10.0+25107+6b50279c, +2 more
    fixed: vendor fix RHSA-2026:86203
  • Red Hat Enterprise Linux AppStream (v. 9) golang 1.26.10-1.el9_8, go-toolset 1.26.10-1.el9_8, golang-bin 1.26.10-1.el9_8, golang-src 1.26.10-1.el9_8, golang-misc 1.26.10-1.el9_8, golang-race 1.26.10-1.el9_8, +1 more
    fixed: vendor fix RHSA-2026:86196
  • Red Hat Enterprise Linux AppStream (v. 10) golang 1.26.10-1.el10_2, go-toolset 1.26.10-1.el10_2, golang-bin 1.26.10-1.el10_2, golang-src 1.26.10-1.el10_2, golang-misc 1.26.10-1.el10_2, golang-race 1.26.10-1.el10_2, +1 more
    fixed: vendor fix RHSA-2026:86093
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) delve 1.26.1-1.module+el8.4.0+25181+7ce5b91c, golang 1.26.10-2.module+el8.4.0+25201+9a419e96, go-toolset 1.26.10-2.module+el8.4.0+25201+9a419e96, golang-bin 1.26.10-2.module+el8.4.0+25201+9a419e96, golang-src 1.26.10-2.module+el8.4.0+25201+9a419e96, golang-misc 1.26.10-2.module+el8.4.0+25201+9a419e96, +2 more
    fixed: vendor fix RHSA-2026:90994
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) delve 1.26.1-1.module+el8.6.0+24782+a062e766, golang 1.26.10-4.module+el8.6.0+25114+90ecdb41, go-toolset 1.26.10-4.module+el8.6.0+25114+90ecdb41, golang-bin 1.26.10-4.module+el8.6.0+25114+90ecdb41, golang-src 1.26.10-4.module+el8.6.0+25114+90ecdb41, golang-misc 1.26.10-4.module+el8.6.0+25114+90ecdb41, +2 more
    fixed: vendor fix RHSA-2026:87246
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) delve 1.26.1-1.module+el8.8.0+24781+86ad105d, golang 1.26.10-4.module+el8.8.0+25113+a148ecc0, go-toolset 1.26.10-4.module+el8.8.0+25113+a148ecc0, golang-bin 1.26.10-4.module+el8.8.0+25113+a148ecc0, golang-src 1.26.10-4.module+el8.8.0+25113+a148ecc0, golang-misc 1.26.10-4.module+el8.8.0+25113+a148ecc0, +2 more
    fixed: vendor fix RHSA-2026:87245
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) golang 1.26.10-1.el9_2, go-toolset 1.26.10-1.el9_2, golang-bin 1.26.10-1.el9_2, golang-src 1.26.10-1.el9_2, golang-misc 1.26.10-1.el9_2, golang-race 1.26.10-1.el9_2, +1 more
    fixed: vendor fix RHSA-2026:87041
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) golang 1.26.10-1.el9_4, go-toolset 1.26.10-1.el9_4, golang-bin 1.26.10-1.el9_4, golang-src 1.26.10-1.el9_4, golang-misc 1.26.10-1.el9_4, golang-race 1.26.10-1.el9_4, +1 more
    fixed: vendor fix RHSA-2026:87042
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) golang 1.26.10-1.el10_0, go-toolset 1.26.10-1.el10_0, golang-bin 1.26.10-1.el10_0, golang-src 1.26.10-1.el10_0, golang-misc 1.26.10-1.el10_0, golang-race 1.26.10-1.el10_0, +1 more
    fixed: vendor fix RHSA-2026:87040
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) golang 1.26.10-1.el9_6, go-toolset 1.26.10-1.el9_6, golang-bin 1.26.10-1.el9_6, golang-src 1.26.10-1.el9_6, golang-misc 1.26.10-1.el9_6, golang-race 1.26.10-1.el9_6, +1 more
    fixed: vendor fix RHSA-2026:87043
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) delve 1.26.1-1.module+el8.4.0+25181+7ce5b91c, golang 1.26.10-2.module+el8.4.0+25201+9a419e96, go-toolset 1.26.10-2.module+el8.4.0+25201+9a419e96, golang-bin 1.26.10-2.module+el8.4.0+25201+9a419e96, golang-src 1.26.10-2.module+el8.4.0+25201+9a419e96, golang-misc 1.26.10-2.module+el8.4.0+25201+9a419e96, +2 more
    fixed: vendor fix RHSA-2026:90994
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) delve 1.26.1-1.module+el8.6.0+24782+a062e766, golang 1.26.10-4.module+el8.6.0+25114+90ecdb41, go-toolset 1.26.10-4.module+el8.6.0+25114+90ecdb41, golang-bin 1.26.10-4.module+el8.6.0+25114+90ecdb41, golang-src 1.26.10-4.module+el8.6.0+25114+90ecdb41, golang-misc 1.26.10-4.module+el8.6.0+25114+90ecdb41, +2 more
    fixed: vendor fix RHSA-2026:87246

6 more fixed, 5 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
total
Assessed
30 d ago

Exploit prediction

0.86% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
OSV 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Affected packages

ecosystem package affected fixed in
bitnami golang
<1.26.9
>=1.27.0-0, <1.27.2
1.26.9
1.27.2
go stdlib
<1.26.9
>=1.27.0-0, <1.27.2
1.26.9
1.27.2
go golang.org/x/net
<0.60.0
0.60.0

Affected products

  • Go standard library net/http
  • Go standard library net/http/internal/http2
  • golang.org/x/net golang.org/x/net/http2

Classification

Weakness
  • CWE-675 Multiple Operations on Resource in Single-Operation Context

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.