CVE-2025-27109 Lack of Escaping of HTML in JSX Fragments allows for Cross-site Scripting in solid-js
Attackers can execute arbitrary scripts via unescaped HTML in JSX fragments, requiring users to upgrade the solid-js library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-27109?
CVE-2025-27109 is a high-severity cross-site scripting vulnerability in solidjs solid, published on 21 Feb 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
solid-js is a declarative, efficient, and flexible JavaScript library for building user interfaces. In affected versions Inserts/JSX expressions inside illegal inlined JSX fragments lacked escaping, allowing user input to be rendered as HTML when put directly inside JSX fragments. This issue has been addressed in version 1.9.4 and all users are advised to upgrade. There are no known workarounds for this vulnerability.
Which versions are affected by CVE-2025-27109?
2 open source packages ship an affected version, including solid-js.
| Package | Affected | Fixed in |
|---|---|---|
solid-js npm | All versions | 1.9.4 |
solid-js npm | All versions | 1.9.4 |
How do I fix CVE-2025-27109?
Upgrade solid-js to 1.9.4 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-2025-27109 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-27109 exists.
Sources
Also known as GHSA-3qxh-p7jc-5xh6.