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CVE-2025-66565
December 09, 2025
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.
Affected Packages
https://github.com/gofiber/utils.git (GITHUB):
Affected version(s) >=v1.0.0 <v2.0.0-rc.4
Fix Suggestion:
Update to version v2.0.0-rc.4
github.com/gofiber/utils/v2 (GO):
Affected version(s) >=v2.0.0-beta.1 <v2.0.0-rc.4
Fix Suggestion:
Update to version v2.0.0-rc.4
github.com/gofiber/utils (GO):
Affected version(s) >=v0.0.1 <v1.2.0
Fix Suggestion:
Update to version v1.2.0
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CVSS v4
Base Score:
9.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
LOW
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
9.4
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
LOW
Weakness Type (CWE)
Unchecked Return Value
Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
Insufficient Entropy
EPSS
Base Score:
0.07