CVE-2026-44332: GoFiber Vulnerable to Username Enumeration via Timing Oracle in BasicAuth Default Authorizer

July 2, 2026

The default Authorizer function in GoFiber’s BasicAuth middleware uses short-circuit evaluation that skips password hash comparison for non-existent usernames. With bcrypt-hashed passwords (the primary use case), the timing difference between a valid and invalid username is approximately 1,000,000:1 (~100ms vs ~100ns), enabling reliable remote username enumeration.

References

github.com/advisories/GHSA-g5vh-55hw-rxm8
github.com/gofiber/fiber/security/advisories/GHSA-g5vh-55hw-rxm8
nvd.nist.gov/vuln/detail/CVE-2026-44332

Code Behaviors & Features

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