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UtilsApplication · Gofiber

CVE-2025-66565

CRITICAL · 9.8 CVSS v3.1 Published 2025-12-09
Fix available
A fix is available. Upgrade to after 1.2.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Fiber Utils versions 2.0.0-rc.3 and below contain a critical vulnerability where UUID generation functions silently fall back to predictable values (including zero UUID) when crypto/rand.Read() fails, compromising security-critical operations.

MitigationUpgrade fiber utils to version 2.0.0-rc.4 or later to obtain the patched library that properly handles crypto/rand failures.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
UtilsApplication
Affected:<= 1.2.0= 2.0.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Gofiber Utils version
    Run 'go list -m all | grep fiber' or inspect the go.mod file for 'github.com/gofiber/utils' to find the installed version
    Affected if The version is 2.0.0 or 1.2.0 or lower (e.g., 1.2.0, 1.1.0, etc.)
  2. Locate UUID generation usage
    Search codebase for imports of 'github.com/gofiber/utils' and usage of UUID-related functions such as uuid.New(), uuid.NewString(), or similar UUID generation methods
    Affected if UUID functions from Gofiber Utils are called in the codebase
  3. Check for fallback behavior triggers
    Review code paths where crypto/rand.Read() could fail (e.g., low entropy conditions, restricted /dev/urandom access) and whether the application continues execution after UUID generation calls
    Affected if The application does not validate UUID return values or does not fail when crypto/rand.Read() fails, allowing predictable UUIDs to be used

A user is affected if their project uses Gofiber Utils version 1.2.0 or lower, or exactly version 2.0.0, and invokes UUID generation functions from this library in security-critical operations.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 1.2.0
Vendor patch github.com →
Interim mitigation

Upgrade fiber utils to version 2.0.0-rc.4 or later to obtain the patched library that properly handles crypto/rand failures.

Recommended fix High confidence

v2.0.0-rc.4

  1. Run `go get -u github.com/gofiber/[email protected]` to upgrade to the fixed version
  2. Alternatively, update the version in go.mod to `github.com/gofiber/utils v2.0.0-rc.4` and run `go mod tidy`
  3. Verify the upgrade was successful by running `go list -m github.com/gofiber/utils`
  4. If using module version pinning, ensure the version resolves to 2.0.0-rc.4 or later
  5. Review application code to ensure any error handling logic around UUID generation is consistent with the fixed behavior (functions will now return errors instead of predictable UUIDs on crypto/rand failure)
Caveat Upgrade from 1.x to 2.x may introduce breaking changes beyond this security fix; review Fiber Utils v2.0.0 release notes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Utils Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-66565 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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