CVE-2025-66020 Valibot has a ReDoS vulnerability in `EMOJI_REGEX`
Attackers can cause excessive CPU consumption and denial of service via malicious strings in the emoji validation regex.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-66020?
CVE-2025-66020 is a high-severity denial of service vulnerability in open-circle valibot, published on 26 Nov 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Valibot helps validate data using a schema. In versions from 0.31.0 to 1.1.0, the EMOJI_REGEX used in the emoji action is vulnerable to a Regular Expression Denial of Service (ReDoS) attack. A short, maliciously crafted string (e.g., <100 characters) can cause the regex engine to consume excessive CPU time (minutes), leading to a Denial of Service (DoS) for the application. This issue has been patched in version 1.2.0.
Weakness: CWE-1333
Which versions are affected by CVE-2025-66020?
2 open source packages ship an affected version, including valibot.
| Package | Affected | Fixed in |
|---|---|---|
valibot npm | From 0.31.0 | 1.2.0 |
valibot npm | From 0.31.0 | 1.2.0 |
How do I fix CVE-2025-66020?
Upgrade valibot to 1.2.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-66020 being exploited?
There is no known exploitation of CVE-2025-66020 in the wild and no public exploit code.
Sources
Also known as GHSA-vqpr-j7v3-hqw9, MINI-743g-2fw3-hw3q.