CVE-2021-21353

Remote code execution in pug

publishedCWE-74

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 packages including "pug", "pug-code-gen". pug-code-gen has a backported fix at version 2.0.3. This advisory is not exploitable if there is no way for un-trusted input to be passed to pug as the `pretty` option, e.g. if you compile templates in advance before applying user input to them, you do not need to upgrade.

Technical severity6.8 mediumCVSS 3.1 · CNA: GitHub_M

Published2021-03-03Source updated 2026-11-02

Collected2026-11-023 attributed sources

Fixes and workarounds

Fix

pug (npm): OSV reports a fixed version 3.0.1. Check the advisory for supported release branches.

Source: OSV GHSA-p493-635q-r6gr

Fix

pug-code-gen (npm): OSV reports a fixed version 2.0.3. Check the advisory for supported release branches.

Source: OSV GHSA-p493-635q-r6gr

Fix

pug-code-gen (npm): OSV reports a fixed version 3.0.2. Check the advisory for supported release branches.

Source: OSV GHSA-p493-635q-r6gr

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
pug pugjs	< 3.0.1 (affected)	CNA: GitHub_M
pug `pug` npm	≥ 0; < 3.0.1 (affected, semver); OSV events: introduced 0; fixed 3.0.1 Source events (semver) `[ { "introduced": "0" }, { "fixed": "3.0.1" } ]` Other versions: unaffected	OSV GHSA-p493-635q-r6gr
pug-code-gen `pug-code-gen` npm	≥ 0; < 2.0.3 (affected, semver); OSV events: introduced 0; fixed 2.0.3 Source events (semver) `[ { "introduced": "0" }, { "fixed": "2.0.3" } ]` Other versions: unaffected	OSV GHSA-p493-635q-r6gr
pug-code-gen `pug-code-gen` npm	≥ 3.0.0; < 3.0.2 (affected, semver); OSV events: introduced 3.0.0; fixed 3.0.2 Source events (semver) `[ { "introduced": "3.0.0" }, { "fixed": "3.0.2" } ]` Other versions: unaffected	OSV GHSA-p493-635q-r6gr

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
3.1 / 6.8 medium	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N`	CNA: GitHub_M

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://github.com/pugjs/pug/security/advisories/GHSA-p493-635q-r6grCNA: GitHub_M · x_refsource_CONFIRM
https://github.com/pugjs/pug/issues/3312CNA: GitHub_M · x_refsource_MISC
https://github.com/pugjs/pug/pull/3314CNA: GitHub_M · x_refsource_MISC
https://github.com/pugjs/pug/commit/991e78f7c4220b2f8da042877c6f0ef5a4683be0CNA: GitHub_M · x_refsource_MISC
https://github.com/pugjs/pug/releases/tag/pug%403.0.1CNA: GitHub_M · x_refsource_MISC
https://www.npmjs.com/package/pugCNA: GitHub_M · x_refsource_MISC
https://www.npmjs.com/package/pug-code-genCNA: GitHub_M · x_refsource_MISC
https://github.com/pugjs/pug/security/advisories/GHSA-p493-635q-r6grADP: CVE · x_refsource_CONFIRM, x_transferred
https://github.com/pugjs/pug/issues/3312ADP: CVE · x_refsource_MISC, x_transferred
https://github.com/pugjs/pug/pull/3314ADP: CVE · x_refsource_MISC, x_transferred
https://github.com/pugjs/pug/commit/991e78f7c4220b2f8da042877c6f0ef5a4683be0ADP: CVE · x_refsource_MISC, x_transferred
https://github.com/pugjs/pug/releases/tag/pug%403.0.1ADP: CVE · x_refsource_MISC, x_transferred
https://www.npmjs.com/package/pugADP: CVE · x_refsource_MISC, x_transferred
https://www.npmjs.com/package/pug-code-genADP: CVE · x_refsource_MISC, x_transferred
https://github.com/advisories/GHSA-p493-635q-r6grOSV / GitHub Security Advisories · advisory
https://osv.dev/vulnerability/GHSA-p493-635q-r6grOSV / GitHub Security Advisories · osv

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