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CVE-2025-66565

31
FAUCET Score

CVE-2025-66565 describes a critical vulnerability in Fiber Utils versions 2.0.0-rc.3 and below, where a failure in the system's cryptographic random number generator (crypto/rand) causes UUID generation functions to silently fall back to predictable values, including the zero UUID. This flaw, rated 9.8 Critical (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), allows unauthenticated attackers to compromise the security of all Fiber applications relying on these functions for security-critical operations. While the vulnerability has a high FAUCET Risk Score of 92/100, there is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion. The issue is resolved in Fiber Utils version 2.0.0-rc.4.

Impacted Technologies

VendorProductVersion(s)CPE
<= 1.2.0CPE matchmatch criteria
cpe:2.3:a:gofiber:utils:*:*:*:*:*:go:*:*
2.0.0CPE matchmatch criteria
cpe:2.3:a:gofiber:utils:2.0.0:beta1:*:*:*:go:*:*
2.0.0CPE matchmatch criteria
cpe:2.3:a:gofiber:utils:2.0.0:beta10:*:*:*:go:*:*
2.0.0CPE matchmatch criteria
cpe:2.3:a:gofiber:utils:2.0.0:beta11:*:*:*:go:*:*
2.0.0CPE matchmatch criteria
cpe:2.3:a:gofiber:utils:2.0.0:beta12:*:*:*:go:*:*

CVSS Data

CVSS version used by this source: 4.0

9.3CRITICAL

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:X/V:X/RE:X/U:X

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
VS Confidentiality
HIGH
VS Integrity
HIGH
VS Availability
LOW
SS Confidentiality
NONE
SS Integrity
NONE
SS Availability
NONE
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.41%
Probability of exploitation in next 30 days
EPSS Percentile
33.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0041 is in the 10th percentile among its peer group of 36,829 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

github_advisorypatch availablevia nvd_reference
View patch
gopatch availablevia ghsa
Product: github.com/gofiber/utils/v2Fixed in: 2.0.0-rc.4
gopatch availablevia ghsa
Product: github.com/gofiber/utilsFixed in: 1.2.0

Vendor Advisories (1)

goGHSA-m98w-cqp3-qcqrcritical

Fiber Utils UUIDv4 and UUID Silent Fallback to Predictable Values

Dec 8, 2025

References

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