Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) Affecting github.com/gofiber/utils/v2 package, versions <1.2.0>=2.0.0-beta.1 <2.0.0-rc.4
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published10 Dec 2025
- disclosed8 Dec 2025
- creditUnknown
Introduced: 8 Dec 2025
CVE-2025-66565 (opens in a new tab)How to fix?
Upgrade github.com/gofiber/utils/v2 to version 1.2.0, 2.0.0-rc.4 or higher.
Overview
Affected versions of this package are vulnerable to Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) due to the UUIDv4 and UUID functions silently returning predictable values, such as the zero UUID, when the cryptographic random number generator fails. An attacker can compromise the integrity and confidentiality of security-sensitive identifiers by triggering or exploiting failures in the system's entropy source, leading to predictable session IDs, CSRF tokens, authentication tokens, and widespread identifier collisions across the application.
Note: Applications running on Go 1.24 or above are not vulnerable because Rand() panics rather than falling back to predictable UUID assignment.
Workaround
This vulnerability can be mitigated by replacing usage of the affected functions with a secure alternative, such as using uuid.New() from a trusted library.