CVE-2019-20174 auth0-lock vulnerable to XSS via unsanitized placeholder property

Medium 6.1 Published 3 Feb 2020 Updated 5 Aug 2024

Attackers can execute arbitrary scripts via XSS in Auth0 Lock when using untrusted placeholders in additional sign-up fields.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: Available

What is CVE-2019-20174?

CVE-2019-20174 is a medium-severity cross-site scripting vulnerability in n/a, published on 3 Feb 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Auth0 Lock before 11.21.0 allows XSS when additionalSignUpFields is used with an untrusted placeholder.

Weakness: CWE-79

Which versions are affected by CVE-2019-20174?

2 open source packages ship an affected version, including auth0-lock. It affects 1 product.

Package	Affected	Fixed in
`auth0-lock` npm	All versions	`11.21.0`
`auth0-lock` npm	All versions	`11.21.0`

Products include Auth0 Lock.

How do I fix CVE-2019-20174?

Upgrade auth0-lock to 11.21.0 or later.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2019-20174 being exploited?

There is no known exploitation of CVE-2019-20174 in the wild and no public exploit code.

Sources

Also known as GHSA-w2pf-g6r8-pg22.