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Critical 9.2Published Feb 9, 2026

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

Updated under an hour ago ()

Does this affect you?

It affects gofiber fiber. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
9.2 CRITICAL (v4.0, CNA)CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
Weakness (CWE)
CWE-338
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Analyzed
Record last updated
Feb 10, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
gofiber fiber
gofiber:fiber (from the name)
before 2.52.11
CNA record
gofiber fiber
gofiber:fiber
before 2.52.11
NVD

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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