VulnerabilityAnalyzed

CVE-2025-66630

This is especially impactful because many Fiber v2 middleware components (session middleware, CSRF, rate limiting, request-ID generation, etc.) default to using utils.UUIDv4().

CRITICAL 9.2EPSS 0.49%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.49%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 4.0: 9.2 CRITICALCVSS:4.0/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/M
EPSS: 0.49% probability · 41th percentile
CISA KEV: Not listed
Weakness: CWE-338
Affected: gofiber/fiber
Source: security-advisories@github.com

References

https://github.com/gofiber/fiber/commit/eb874b6f6c5896b968d9b0ab2b56ac7052cb0ee1Patch
https://github.com/gofiber/fiber/releases/tag/v2.52.11Product, Release Notes
https://github.com/gofiber/fiber/security/advisories/GHSA-68rr-p4fp-j59vVendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.