Cryptographic Weakness in Fiber Utils Vulnerability Affecting Fiber
CVE-2025-66565

9.3CRITICAL

Key Information:

Vendor

Gofiber

Status
Utils
Vendor
CVE Published:
9 December 2025

What is CVE-2025-66565?

The Fiber Utils library contains functions that inadvertently fall back to generating predictable UUIDs when the cryptographic random number generator fails. This behavior compromises the integrity of any application relying on these functions for cryptographic security, as it may expose sensitive operations to potential exploits. The issue arises from failures in crypto/rand.Read(), revealing predictable UUIDs, including the zero UUID, which can undermine the overall security posture of applications built with Fiber. This vulnerability is resolved in version 2.0.0-rc.4.

Affected Version(s)

utils github.com/gofiber/utils <= 1.2.0 <= github.com/gofiber/utils 1.2.0

utils github.com/gofiber/utils/v2 < 2.0.0-rc.4 < github.com/gofiber/utils/v2 2.0.0-rc.4

References

https://github.com/gofiber/utils/security/advisories/GHSA...
x_refsource_CONFIRM
https://github.com/gofiber/utils/commit/6c6cf047032b9c8df...
x_refsource_MISC

CVSS V4

Score:
9.3
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

JSON
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