Is CVE-2025-66565 in the CISA KEV catalog?

No. CVE-2025-66565 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2025-66565?

CVE-2025-66565 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2025-66565?

CVE-2025-66565 has an EPSS score of 0.40% (32th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2025-66565

CRITICAL

9.8

CVSS v3

NVD

Description

Fiber Utils is a collection of common functions created for Fiber. In versions 2.0.0-rc.3 and below, when the system's cryptographic random number generator (crypto/rand) fails, both functions silently fall back to returning predictable UUID values, including the zero UUID "00000000-0000-0000-0000-000000000000". The vulnerability occurs through two related but distinct failure paths, both ultimately caused by crypto/rand.Read() failures, compromising the security of all Fiber applications using these functions for security-critical operations. This issue is fixed in version 2.0.0-rc.4.

CWE-252 CWE-331 CWE-338

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.40%probability of exploitation in 30 days

32ndpercentile

Low risk: more likely to be exploited than 32% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-12-11.