CVE-2025-56200 validator.js has a URL validation bypass vulnerability in its isURL function
Attackers can bypass URL validation in validator.js to execute XSS or open redirects due to protocol parsing differences with browsers.
- 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-2025-56200?
CVE-2025-56200 is a medium-severity cross-site scripting vulnerability in n/a, published on 30 Sep 2025. 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
A URL validation bypass vulnerability exists in validator.js through version 13.15.15. The isURL() function uses '://' as a delimiter to parse protocols, while browsers use ':' as the delimiter. This parsing difference allows attackers to bypass protocol and domain validation by crafting URLs leading to XSS and Open Redirect attacks.
Weakness: CWE-79
Which versions are affected by CVE-2025-56200?
2 open source packages ship an affected version, including validator. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
validator npm | All versions | 13.15.20 |
validator npm | All versions | 13.15.20 |
Products include Validator Project Validator.
How do I fix CVE-2025-56200?
Upgrade validator to 13.15.20 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-2025-56200 being exploited?
There is no known exploitation of CVE-2025-56200 in the wild and no public exploit code.
Other vulnerabilities in n/a
Sources
Also known as CLSA-2026-1784769499, CLSA-2026-1789161501, GHSA-9965-vmph-33xx, MINI-6hx5-73r5-8c3v, MINI-85p5-p97c-w7m9, MINI-98rp-vv2g-9x4v and 2 more.