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Fencer Vulns
high 7.5

CVE-2021-33194 json

golang.org/x/net/html Infinite Loop vulnerability

published 2021-05-26 5 y ago modified 2026-09-10 1 mo ago also BIT-golang-2021-33194 , EUVD-2022-3094 , GHSA-83g2-8m93-v3w7 , GO-2021-0238

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
7.5%
EPSS 7.5% chance of exploitation in 30 days, percentile 94%
public exploits
0
none known

Summary

golang.org/x/net before v0.0.0-20210520170846-37e1c6afe023 allows attackers to cause a denial of service (infinite loop) via crafted ParseFragment input.

Patch / fix

  • go golang.org/x/net 0.0.0-20210520170846-37e1c6afe023
  • bitnami golang 1.15.12, 1.16.4
  • golang net 0.0.0-20210520170846-37e1c6afe023
  • golang networking 0.0.0-20210520170846-37e1c6afe023
  • golang-golang-x-net Debian 14, Debian 13, Debian 12 1:0.0+git20210119.5f4716e+dfsg-4

debian advisories DEBIAN-CVE-2021-33194

  • lxd Ubuntu Pro 18.04 LTS 3.0.3-0ubuntu1~18.04.2+esm2
  • golang-golang-x-net-dev Ubuntu Pro 20.04 LTS 1:0.0+git20190811.74dc4d7+dfsg-1ubuntu0.1~esm2

ubuntu advisories UBUNTU-CVE-2021-33194

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

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-2021-33194 updated cvss 7.5

golang: x/net/html: infinite loop in ParseFragment

  • Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/cluster-logging-rhel8-operator
    affected: no fix planned “Will not fix”
  • Red Hat OpenShift Service Mesh 2.0 servicemesh, servicemesh-mixc, servicemesh-mixs, servicemesh-istioctl, servicemesh-pilot-agent, servicemesh-pilot-discovery
    affected: no fix available
  • Red Hat Ceph Storage 2 golang, grafana, golang-bin, golang-src Red Hat Ceph Storage 3 golang, grafana, golang-bin, golang-src, grafana-container, prometheus-node-exporter Red Hat Enterprise Linux 7 golang, golang-bin, golang-src, golang-misc, golang-tests
    affected: no fix planned “Out of support scope”
  • Red Hat OpenShift Container Platform 4 openshift, openshift-clients, openshift-kubelet, openshift4/ose-cli, openshift-hyperkube, openshift4/ose-tests, +34 more
    affected: no fix available, no fix planned “Will not fix”
  • Red Hat OpenShift Container Platform Assisted Installer 1 rhai-tech-preview/assisted-installer-rhel8, rhai-tech-preview/assisted-installer-agent-rhel8, rhai-tech-preview/assisted-installer-reporter-rhel8
    affected: no fix available
  • Red Hat Openshift Container Storage 4 mcg, ocs4/cephcsi-rhel8, ocs4/mcg-rhel8-operator, ocs4/ocs-rhel8-operator
    affected: no fix available “Fix deferred”
  • Red Hat OpenShift Logging 5.3 openshift-logging/elasticsearch-proxy-rhel8 v1.0.0-44, openshift-logging/elasticsearch-rhel8-operator v5.3.0-19
    fixed: vendor fix RHSA-2021:4627
  • Red Hat OpenShift Container Platform 4.8 openshift4/ose-cluster-node-tuning-operator v4.8.0-202107091725.p0.git.6be3f67.assembly.stream
    fixed: vendor fix RHSA-2021:2438
show 2 more
  • Red Hat OpenShift Container Platform 4.9 openshift4/ose-oauth-proxy v4.9.0-202109302016.p0.git.9ea1ebc.assembly.stream
    fixed: vendor fix RHSA-2021:3759
  • Red Hat OpenShift Logging 5.3 openshift-logging/fluentd-rhel8 v1.7.4-42, openshift-logging/kibana6-rhel8 v6.8.1-49, openshift-logging/eventrouter-rhel8 v0.3.0-42, openshift-logging/elasticsearch6-rhel8 v6.8.1-42, openshift-logging/logging-curator5-rhel8 v5.8.1-29, openshift-logging/elasticsearch-operator-bundle v5.3.0-67, +3 more Red Hat OpenShift Serverless cli, knative-serving knative-serving, openshift-serverless-1/kn-eventing-apiserver-receive-adapter-rhel9 Red Hat Ceph Storage 4 rhceph/rhceph-4-dashboard-rhel8 Red Hat Enterprise Linux 7 buildah Red Hat Enterprise Linux 8 golang, buildah, go-toolset, golang-bin, golang-src, golang-misc, +3 more Red Hat Enterprise Linux 9 golang, buildah, go-toolset, golang-bin, golang-src, golang-misc, +3 more
    +8 more products
    Red Hat OpenShift Container Platform 4 cri-o, cri-tools, openshift4/compliance-rhel8-operator Red Hat OpenShift Container Platform 4.8 openshift4/ose-cli v4.8.0-202106291725.p0.git.1077b05.assembly.stream, openshift4/ose-pod v4.8.0-202107161820.p0.git.051ac4f.assembly.stream, openshift4/ose-etcd v4.8.0-202106152230.p0.git.aefa6bf.assembly.stream, openshift4/ose-tests v4.8.0-202107131424.p0.git.0d958c3.assembly.stream, openshift4/ose-console v4.8.0-202107010336.p0.git.188a490.assembly.stream, openshift4/ose-coredns v4.8.0-202106291913.p0.git.642b46e.assembly.stream, +135 more Red Hat OpenShift Container Platform 4.9 openshift4/ose-cli v4.9.0-202109302317.p0.git.96e95ce.assembly.stream, openshift4/ose-pod v4.9.0-202110080828.p0.git.894a78b.assembly.stream, openshift4/ose-etcd v4.9.0-202109302317.p0.git.5c1feaf.assembly.stream, openshift4/ose-console v4.9.0-202110130449.p0.git.8c077e4.assembly.rc.8, openshift4/ose-tests v4.9.0-202110011028.p0.git.6105395.assembly.stream, openshift4/ose-coredns v4.9.0-202109302317.p0.git.3cb11c0.assembly.stream, +141 more Red Hat Openshift Container Storage 4 ocs4/ocs-must-gather-rhel8, ocs4/rook-ceph-rhel8-operator Red Hat OpenShift Virtualization 2 kubevirt, virt-api-container, kubemacpool-container, virt-handler-container, bridge-marker-container, virt-launcher-container, +16 more Red Hat OpenStack Platform 16.1 etcd Red Hat OpenStack Platform 16.2 etcd Red Hat Storage 3 etcd, golang, heketi, grafana, golang-bin, golang-src, +5 more
    not affected: vulnerable code not present

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

Exploit prediction

7.49% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
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
go golang.org/x/net
<0.0.0-20210520170846-37e1c6afe023
0.0.0-20210520170846-37e1c6afe023
bitnami golang
<1.15.12
>=1.16.0, <1.16.4
1.15.12
1.16.4

Classification

Weakness
  • CWE-835 Loop with Unreachable Exit Condition

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: Improve version ranges to indicate fix.