Regular Expression Denial of Service Vulnerability in Valibot by Open Circle
CVE-2025-66020

7.5HIGH

Key Information:

Vendor

Open-circle

Status
Valibot
Vendor
CVE Published:
26 November 2025

What is CVE-2025-66020?

Valibot, a data validation tool, has a vulnerability within its emoji handling mechanism due to a flawed EMOJI_REGEX implementation. Specifically, versions 0.31.0 through 1.1.0 are susceptible to a Regular Expression Denial of Service (ReDoS) attack. Attackers can exploit this flaw by supplying a carefully crafted input string of fewer than 100 characters, which forces the regular expression engine to consume an excessive amount of CPU resources. This can result in prolonged application hang times, effectively rendering the service unavailable. The issue has been resolved in version 1.2.0, which patches the regex flaw, enhancing overall stability and performance.

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Deploy the Patch

Affected Version(s)

valibot >= 0.31.0, < 1.2.0

References

https://github.com/open-circle/valibot/security/advisorie...
x_refsource_CONFIRM
https://github.com/open-circle/valibot/commit/cfb799db301...
x_refsource_MISC

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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