GHSA-cg48-9hh2-x6mx HTML Injection in preact
Attackers can inject JavaScript via unsanitized JSON input in preact, leading to Cross-Site Scripting and potential code execution.
- 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 GHSA-cg48-9hh2-x6mx?
GHSA-cg48-9hh2-x6mx is a cross-site scripting vulnerability in preact, published on 2 Sep 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
Versions of preact 10.x on prerelease tags alpha and beta prior to 10.0.0-beta.1 are vulnerable to HTML Injection. Due to insufficient input validation the package allows attackers to inject JavaScript objects as virtual-dom nodes, which may lead to Cross-Site Scripting. This requires user input parsed with JSON.parse() to be passed directly into JSX without sanitization.
Recommendation
Upgrade to version 10.0.0-beta.1.
Which versions are affected by GHSA-cg48-9hh2-x6mx?
2 open source packages ship an affected version, including preact.
| Package | Affected | Fixed in |
|---|---|---|
preact npm | From 10.0.0-alpha.0 | 10.0.0-beta.1 |
preact npm | From 10.0.0-alpha.0 | 10.0.0-beta.1 |
How do I fix GHSA-cg48-9hh2-x6mx?
Upgrade preact to 10.0.0-beta.1 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 GHSA-cg48-9hh2-x6mx being exploited?
There is no known exploitation of GHSA-cg48-9hh2-x6mx in the wild and no public exploit code.