CVE-2025-66630 Fiber insecurely fallsback in utils.UUIDv4() / utils.UUID() — predictable / zero‑UUID on crypto/rand failure

What is CVE-2025-66630?

CVE-2025-66630 is a critical vulnerability in gofiber fiber, published on 9 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-338

Which versions are affected by CVE-2025-66630?

4 open source packages ship an affected version, including github.com/gofiber/fiber/v2 and github.com/gofiber/fiber. It affects 1 product.

Products include Gofiber Fiber.

How do I fix CVE-2025-66630?

Upgrade github.com/gofiber/fiber/v2 to 2.52.11 or later.

Is CVE-2025-66630 being exploited?

There is no known exploitation of CVE-2025-66630 in the wild and no public exploit code.

Other vulnerabilities in gofiber fiber

• CVE-2024-38513 Fiber Session Middleware Token Injection Vulnerability Critical 10.0
• CVE-2023-45128 CSRF Token Reuse Vulnerability in fiber Critical 10.0
• CVE-2024-25124 Fiber has Insecure CORS Configuration, Allowing Wildcard Origin with Credentials Critical 9.4
• CVE-2025-54801 Fiber Susceptible to Crash via `BodyParser` Due to Unvalidated Large Slice Index in Decoder High 8.7
• CVE-2023-45141 CSRF Token Validation Vulnerability in fiber High 8.6

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-68rr-p4fp-j59v, GO-2026-4471.