CVE-2025-66020
HIGHCVE-2025-66020 is a high-severity (CVSS 7.5) CWE-1333 vulnerability in valibot. O3 Security confirms whether CVE-2025-66020 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Valibot has a ReDoS vulnerability in `EMOJI_REGEX`
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
valibotnpmDescription
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | valibot | ≥ 0.31.0&&< 1.2.0 | 1.2.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for valibot. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update valibot to 1.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-66020 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2025-66020 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2025-66020. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-66020 in your dependencies?
O3 detects CVE-2025-66020 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.