CVE-2021-21353: Pug is an npm package which is a high-performance template engine

Q: How do I fix CVE-2021-21353?

pug: upgrade to 3.0.1; pug-code-gen: upgrade to 2.0.3, 3.0.2. Exact commands for each OS are on this page.

Q: Is CVE-2021-21353 being exploited?

CVE-2021-21353 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-21353 affect?

CVE-2021-21353 affects pug, pug-code-gen. Severity is medium (CVSS 6.8). Pug is an npm package which is a high-performance template engine. In pug before version 3.0.1, if a remote attacker was able to control the `pretty` option of the pug compiler, e.g. if you spread a user provided object such as the query p

Q: How urgent is CVE-2021-21353?

Priority 57/100. EPSS top 9%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action

This week

MEDIUM 6.8REMOTEUPGRADEUPGRADE

CVE-2021-21353 is a medium-severity flaw (CVSS 6.8) affecting pug, pug-code-gen. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Pug is an npm package which is a high-performance template engine. In pug before version 3.0.1, if a remote attacker was able to control the `pretty` option of the pug compiler, e.g. if you spread a user provided object such as the query parameters of a request into the pug template inputs, it was possible for them to achieve remote code execution on the node.js backend. This is fixed in version 3.0.1. This advisory applies to multiple pug pack

Why this priority

EPSS top 9%: very likely to be exploited
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	6.8 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	4.3% (top 9%)
CISA exploited list	No
Weakness	CWE-74, CWE-94
Published	2021-03-03
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: pugjs

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-03-03 02:15 UTCPublished CVE record published
2026-06-17 03:35 UTCUpdated Record last modified

pugjs pug UPGRADE

Affected: < 3.0.1

Fixed in: 3.0.1

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls pug

2. UPGRADE to 3.0.1

npm install pug@">=3.0.1"

pugjs pug-code-gen UPGRADE

Affected: < 2.0.3 · >= 3.0.0 and < 3.0.2

Fixed in: 2.0.3, 3.0.2

Safe to downgrade to: a release before 3.0.0

1. Check installed version

npm ls pug-code-gen

2. UPGRADE to 2.0.3

npm install pug-code-gen@">=2.0.3"

3. If no update is available yet, DOWNGRADE to a release before 3.0.0

npm view pug-code-gen versions npm install pug-code-gen@"<3.0.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-21353?

pug: upgrade to 3.0.1; pug-code-gen: upgrade to 2.0.3, 3.0.2. Exact commands for each OS are on this page.

Is CVE-2021-21353 being exploited?

CVE-2021-21353 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-21353 affect?

CVE-2021-21353 affects pug, pug-code-gen. Severity is medium (CVSS 6.8). Pug is an npm package which is a high-performance template engine. In pug before version 3.0.1, if a remote attacker was able to control the `pretty` option of the pug compiler, e.g. if you spread a user provided object such as the query p

How urgent is CVE-2021-21353?

Priority 57/100. EPSS top 9%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Node.js vulnerabilities · npm packages vulnerabilities

References

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