NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
🐹
🐹 Go
Not in CISA KEV
HIGH severity

CVE-2021-33194 — x/net

HIGHFix: golang/net@37e1c6a

CVE-2021-33194 is a high-severity (CVSS 7.5) CWE-835 vulnerability in golang.org/x/net. A fix is available for golang.org/x/net — see the affected versions and patch details below.

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

Also known asBIT-golang-2021-33194GHSA-83g2-8m93-v3w7GO-2021-0238
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
7.5%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs95th percentile — riskier than 95% of all scored CVEsHighest risk
0.00%3.23%6.46%9.70%0.1%7.5%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
🐹golang.org/x/net

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

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

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogolang.org/x/netall versions0.0.0-20210520170846-37e1c6afe023go get golang.org/x/net@v0.0.0-20210520170846-37e1c6afe023

Affected Products

2 products · 3 configurations
OS
fedorafedoraproject
1 version
36
Application
gogolang
≥ 1.16.0 && ≤ 1.16.4
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for golang.org/x/net, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update golang.org/x/net to 0.0.0-20210520170846-37e1c6afe023 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-33194 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Red Hat Developer Tools go-toolset-1.14-golang not affected because the vulnerable code is not shipped. This vulnerability within golang and buildah shipped with RHEL-7 are out of support scope. For more information on Red Hat's support scope, visit: https://access.redhat.com/support/policy/updates/errata For RHEL-8's…

ProductFixed inAdvisory
OpenShift Logging 5.3openshift-logging/elasticsearch-proxy-rhel8:v1.0.0-44RHSA-2021:4627
Red Hat OpenShift Container Platform 4.8openshift4/ose-cluster-node-tuning-operator:v4.8.0-202107091725.p0.git.6be3f67.assembly.streamRHSA-2021:2438
Red Hat OpenShift Container Platform 4.9openshift4/ose-oauth-proxy:v4.9.0-202109302016.p0.git.9ea1ebc.assembly.streamRHSA-2021:3759

Frequently Asked Questions

golang.org/x/net before v0.0.0-20210520170846-37e1c6afe023 allows attackers to cause a denial of service (infinite loop) via crafted ParseFragment input.
O3 Security · Impact-Aware SCA

Is CVE-2021-33194 in your dependencies?

Find it across Go, including transitive dependencies.

Scan my dependencies How O3 SCA works
CVE-2021-33194: x/net DoS — Fix Available