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Vulnerabilities

Vulnerability · CVE-2025-66565

Fiber Utils is a collection of common functions created for Fiber.

Published Dec 9, 2025 · catalog updated Dec 9, 2025 · Fiber Utils is a

Last checked Nov 2, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-66565. EPSS is 0.47%. Act only if a listed version of Fiber Utils is a is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Fiber Utils is a).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Critical9.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.47%
Remediation
Version ranges on file
Affected products
vendor gofiber utils github.com/gofiber/utils/v2 < 2.0.0-rc.4

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

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

How to fix CVE-2025-66565

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-66565. EPSS is 0.47%. Act only if a listed version of Fiber Utils is a is installed.

Which versions are affected?

Compare what you have installed with gofiber utils github.com/gofiber/utils/v2 < 2.0.0-rc.4 github.com/gofiber/utils/v2 < 2.0.0-rc.4. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.47%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 9, 2025 · EUVD

    Detected

    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 ultimate

  2. Dec 9, 2025 · EUVD

    Updated

    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 ultimate

Sources

  • CVE.orgVulnerability recordCVE-2025-66565

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-66565

    30-day exploitation probability 0.47%

    first.org
  • EUVDVulnerability recordEUVD-2025-201791

    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 "00000

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 2, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 2, 2026
  • CVE.orgOct 27, 2026
  • EUVDOct 27, 2026