CVE-2025-66565CRITICAL 9.8EPSS p31.8%
CVE-2025-66565CVE-2025-66565
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.
Scoring
| CVSS 3.1 | 9.8 (CRITICAL) |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| EPSS | 0.40% probability of exploitation · percentile 31.8% · 2026-06-19T12:03:05Z |
| Published | 2025-12-09 |
| Last modified | 2025-12-11 |
Underlying weaknesses· 3
References
3
| Type | Target | Confidence | Tier |
|---|---|---|---|
| Weakness | Unchecked Return Valuecwe-252 | 0% | live |
| Weakness | Insufficient Entropycwe-331 | 0% | live |
| Weakness | Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)cwe-338 | 0% | live |
Related by meaning· 6
Nearest entities by semantic similarity across the cs-graph corpus.