CVE-2025-66565
Published: 09 December 2025
Summary
CVE-2025-66565 is a critical-severity Unchecked Return Value (CWE-252) vulnerability in Gofiber Utils. Its CVSS base score is 9.3 (Critical).
Operationally, ranked at the 23.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-201791
Vulnerability details
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".…
more
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.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Approved key-establishment methods mandate sufficient entropy during key generation, eliminating entropy-starved keys.
Security associations share details on cryptographically weak PRNGs, helping avoid their implementation in security-critical functions.