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.
CVE-2021-21353
CVSS base score
6.8 (v3.1)
Severity
MEDIUM
Attack vector
Network
Weakness
CWE-74, CWE-94
Last modified
November 2, 2026
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N
Affected products
pugjs pug
pugjs pug-code-gen
References
- github.com Patch, Third Party Advisory
- github.com Exploit, Patch, Third Party Advisory
- github.com Patch, Third Party Advisory
- github.com Release Notes, Third Party Advisory
- github.com Third Party Advisory
- www.npmjs.com Product, Third Party Advisory
- www.npmjs.com Product, Third Party Advisory
- github.com Patch, Third Party Advisory
- github.com Exploit, Patch, Third Party Advisory
- github.com Patch, Third Party Advisory