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Vulnerability record · CVE-2025-66565 · published 9 December 2025

CVE-2025-66565: Gofiber utils unchecked return value vulnerability

Gofiber · Utils

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.

9.3 CVSS 4.0 Critical EPSS 0.47% · top 62.0% CWE-252 · Unchecked return valueCWE-331 · CWE-331
9.3CVSS 4.0 base score
0.47%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References
17 Jun 2026Last modified by 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.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/gofiber/utils/commit/6c6cf047032b9c8dff43d29f990b4b10e9b02d47 Patch
https://github.com/gofiber/utils/security/advisories/GHSA-m98w-cqp3-qcqr Vendor Advisory
https://github.com/gofiber/utils/security/advisories/GHSA-m98w-cqp3-qcqr Vendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2025-66565), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.