Vulnerability in Gofiber Utils

CVE-2025-66565

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (38.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 38th percentile — 38.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-66565: held from 0.005 to 0.005.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.000

Affected products

  • Gofiber Utils — versions github.com/gofiber/utils <= 1.2.0, github.com/gofiber/utils/v2 < 2.0.0-rc.4, 2.0.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2025-66565?
CVE-2025-66565 is a critical-severity vulnerability in Gofiber Utils, classified under CWE-252. CVSS score: 9.8/10. Published 2025-12-09.
How severe is CVE-2025-66565?
Critical severity. CVSS v3 base score is 9.8 out of 10.