CVE & CISA-KEV Catalog

CVE-2021-33194

HIGHEPSS 94th pctl
7.5
CVSS v3
NVD

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.

How to fix

Remediation Available
golang-golang-x-netDebian
Fixed in:1:0.0+git20210119.5f4716e+dfsg-4CVE-2021-33194
Fixed in:1:0.0+git20210119.5f4716e+dfsg-4CVE-2021-33194
Fixed in:1:0.0+git20210119.5f4716e+dfsg-4CVE-2021-33194
adsysUbuntu
Fixed in:0.9.2~20.04.2ubuntu0.1+esm1USN-8089-3

This Ubuntu release reached end-of-life on 2025-05-31. Extended security maintenance is available until 2030-04-02.

adsys-windowsUbuntu
Fixed in:0.9.2~20.04.2ubuntu0.1+esm1USN-8089-3

This Ubuntu release reached end-of-life on 2025-05-31. Extended security maintenance is available until 2030-04-02.

golang-github-lxc-lxd-devUbuntu
Fixed in:2.0.11-0ubuntu1~16.04.4+esm2USN-8089-3

This Ubuntu release reached end-of-life on 2021-04-02.

golang-go.net-devUbuntu
Fixed in:1:0.0+git20160110.4fd4a9f-1ubuntu0.1~esm2USN-8089-2

This Ubuntu release reached end-of-life on 2021-04-02.

Fixed in:1:0.0+git20170629.c81e7f2+dfsg-2ubuntu0.1~esm2USN-8089-2

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

Fixed in:1:0.0+git20190811.74dc4d7+dfsg-1ubuntu0.1~esm2USN-8089-2

This Ubuntu release reached end-of-life on 2025-05-31. Extended security maintenance is available until 2030-04-02.

golang-golang-x-net-devUbuntu
Fixed in:1:0.0+git20160110.4fd4a9f-1ubuntu0.1~esm2USN-8089-2

This Ubuntu release reached end-of-life on 2021-04-02.

Fixed in:1:0.0+git20170629.c81e7f2+dfsg-2ubuntu0.1~esm2USN-8089-2

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

Fixed in:1:0.0+git20190811.74dc4d7+dfsg-1ubuntu0.1~esm2USN-8089-2

This Ubuntu release reached end-of-life on 2025-05-31. Extended security maintenance is available until 2030-04-02.

jujuUbuntu
Fixed in:2.3.7-0ubuntu0.16.04.1+esm2USN-8089-3

This Ubuntu release reached end-of-life on 2021-04-02.

juju-2.0Ubuntu
Fixed in:2.3.7-0ubuntu0.16.04.1+esm2USN-8089-3

This Ubuntu release reached end-of-life on 2021-04-02.

juju-coreUbuntu
Fixed in:2.3.7-0ubuntu0.16.04.1+esm2USN-8089-3

This Ubuntu release reached end-of-life on 2021-04-02.

lxc2Ubuntu
Fixed in:2.0.11-0ubuntu1~16.04.4+esm2USN-8089-3

This Ubuntu release reached end-of-life on 2021-04-02.

lxdUbuntu
Fixed in:2.0.11-0ubuntu1~16.04.4+esm2USN-8089-3

This Ubuntu release reached end-of-life on 2021-04-02.

Fixed in:3.0.3-0ubuntu1~18.04.2+esm2USN-8089-3

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

lxd-clientUbuntu
Fixed in:2.0.11-0ubuntu1~16.04.4+esm2USN-8089-3

This Ubuntu release reached end-of-life on 2021-04-02.

Fixed in:3.0.3-0ubuntu1~18.04.2+esm2USN-8089-3

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

lxd-toolsUbuntu
Fixed in:2.0.11-0ubuntu1~16.04.4+esm2USN-8089-3

This Ubuntu release reached end-of-life on 2021-04-02.

Fixed in:3.0.3-0ubuntu1~18.04.2+esm2USN-8089-3

This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

7.49%probability of exploitation in 30 days
94thpercentile

High risk: more likely to be exploited than 94% of all known CVEs.

References

Third-Party Advisory1
Other references1

Related Vulnerabilities

Other CWE-835 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2020-13935High7.587%-Fix
CVE-2020-36227High7.578%-Fix
CVE-2022-0778High7.573%-Fix
CVE-2024-20353High8.671%KEV-
CVE-2019-14241High7.570%--
CVE-2017-16944High7.563%-Fix

Common questions

How do I fix CVE-2021-33194?

Published advisories record a fix for 13 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2021-33194 being actively exploited?

Not that we know of. CVE-2021-33194 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 7.5% is the estimated probability that it will be exploited in the next 30 days. That is higher than 94% of all scored CVEs.

How severe is CVE-2021-33194?

CVE-2021-33194 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2021-33194 affect?

Published advisories record a fix for golang-golang-x-net (Debian), adsys (Ubuntu), adsys-windows (Ubuntu), golang-github-lxc-lxd-dev (Ubuntu), and 9 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-17.