How severe is CVE-2025-66020?

CVE-2025-66020 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2025-66020 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-66020?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-66020 have an EU (EUVD) identifier?

Yes. CVE-2025-66020 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-199685.

When was CVE-2025-66020 published?

CVE-2025-66020 was published on 2025-11-26 and last updated on 2026-06-17.

CVE-2025-66020

CVE-2025-66020 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1333.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (21st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-199685
Weakness: CWE-1333
Published: 2025-11-26
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2025-66020?: 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.
How severe is CVE-2025-66020?: CVE-2025-66020 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-66020 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-66020?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-66020 have an EU (EUVD) identifier?: Yes. CVE-2025-66020 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-199685.
When was CVE-2025-66020 published?: CVE-2025-66020 was published on 2025-11-26 and last updated on 2026-06-17.

References

Other CWE-1333 vulnerabilities

CVE-2026-35458 — Critical (CVSS 9.8): Gotenberg is an API for converting document formats. In 8.29.1 and earlier, Gotenberg uses dlclark/regexp2 to compile…
CVE-2023-29486 — Critical (CVSS 9.8): An issue was discovered in Heimdal Thor agent versions 3.4.2 and before 3.7.0 on Windows, allows attackers to bypass…
CVE-2026-25547 — Critical (CVSS 9.2): @isaacs/brace-expansion is a hybrid CJS/ESM TypeScript fork of brace-expansion. Prior to version 5.0.1,…
CVE-2023-29487 — Critical (CVSS 9.1): An issue was discovered in Heimdal Thor agent versions 3.4.2 and before on Windows and 2.6.9 and before on macOS,…
CVE-2026-47138 — High (CVSS 8.7): Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to…
CVE-2025-6998 — High (CVSS 8.7): ReDoS in strip_whitespaces() function in cps/string_helper.py in Calibre Web and Autocaliweb allows unauthenticated…

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