CVE-2025-66630
Fiber insecurely fallsback in utils.UUIDv4() / utils.UUID() — predictable / zero‑UUID on crypto/rand failure
Description
Fiber is an Express inspired web framework written in Go. Before 2.52.11, on Go versions prior to 1.24, the underlying crypto/rand implementation can return an error if secure randomness cannot be obtained. Because no error is returned by the Fiber v2 UUID functions, application code may unknowingly rely on predictable, repeated, or low-entropy identifiers in security-critical pathways. This is especially impactful because many Fiber v2 middleware components (session middleware, CSRF, rate limiting, request-ID generation, etc.) default to using utils.UUIDv4(). This vulnerability is fixed in 2.52.11.
INFO
Published Date :
Feb. 9, 2026, 6:16 p.m.
Last Modified :
Feb. 28, 2026, 12:26 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | [email protected] | ||||
| CVSS 4.0 | CRITICAL | [email protected] |
Solution
- Update Fiber to version 2.52.11 or later.
- Verify secure randomness in critical security pathways.
- Review middleware configurations using UUID generation.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-66630.
| URL | Resource |
|---|---|
| https://github.com/gofiber/fiber/commit/eb874b6f6c5896b968d9b0ab2b56ac7052cb0ee1 | Patch |
| https://github.com/gofiber/fiber/releases/tag/v2.52.11 | Product Release Notes |
| https://github.com/gofiber/fiber/security/advisories/GHSA-68rr-p4fp-j59v | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-66630 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-66630
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-66630 vulnerability anywhere in the article.
-
The Hacker News
Weekly Recap: Outlook Add-Ins Hijack, 0-Day Patches, Wormable Botnet & AI Malware
This week’s recap shows how small gaps are turning into big entry points. Not always through new exploits, often through tools, add-ons, cloud setups, or workflows that people already trust and rarely ... Read more
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CybersecurityNews
Critical UUID Flaw in Fiber v2 on Go 1.24+ Enables Session Hijacking, CSRF Bypass, and Zero-ID DoS Risk
UUID Flaw in Fiber v2 on Go A severe vulnerability has been discovered in Fiber v2, a popular Go web framework, that could allow attackers to hijack user sessions, bypass security protections, and cau ... Read more
-
Daily CyberSecurity
“Fiber” Optic Failure: Predictable UUIDs Expose Go Web Framework to Hijacking
A critical vulnerability has been uncovered in Fiber, the high-performance web framework for Go that powers countless modern web applications. The flaw, tracked as CVE-2025-66630, carries a CVSS score ... Read more
The following table lists the changes that have been made to the
CVE-2025-66630 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Feb. 28, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L Added CPE Configuration AND OR *cpe:2.3:a:gofiber:fiber:*:*:*:*:*:go:*:* versions up to (excluding) 2.52.11 OR cpe:2.3:a:golang:go:*:-:*:*:*:*:*:* versions up to (excluding) 1.24.0 Added Reference Type GitHub, Inc.: https://github.com/gofiber/fiber/commit/eb874b6f6c5896b968d9b0ab2b56ac7052cb0ee1 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/gofiber/fiber/releases/tag/v2.52.11 Types: Product, Release Notes Added Reference Type GitHub, Inc.: https://github.com/gofiber/fiber/security/advisories/GHSA-68rr-p4fp-j59v Types: Vendor Advisory -
New CVE Received by [email protected]
Feb. 09, 2026
Action Type Old Value New Value Added Description Fiber is an Express inspired web framework written in Go. Before 2.52.11, on Go versions prior to 1.24, the underlying crypto/rand implementation can return an error if secure randomness cannot be obtained. Because no error is returned by the Fiber v2 UUID functions, application code may unknowingly rely on predictable, repeated, or low-entropy identifiers in security-critical pathways. This is especially impactful because many Fiber v2 middleware components (session middleware, CSRF, rate limiting, request-ID generation, etc.) default to using utils.UUIDv4(). This vulnerability is fixed in 2.52.11. Added CVSS V4.0 AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-338 Added Reference https://github.com/gofiber/fiber/commit/eb874b6f6c5896b968d9b0ab2b56ac7052cb0ee1 Added Reference https://github.com/gofiber/fiber/releases/tag/v2.52.11 Added Reference https://github.com/gofiber/fiber/security/advisories/GHSA-68rr-p4fp-j59v