CVE-2026-44332 Fiber: Username Enumeration via Timing Oracle in BasicAuth Default Authorizer

What is CVE-2026-44332?

CVE-2026-44332 is a medium-severity vulnerability in gofiber fiber, published on 8 Jul 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. Prior to 3.3.0, the default Authorizer function in the BasicAuth middleware in middleware/basicauth/config.go uses short-circuit evaluation that skips password hash comparison for non-existent usernames, enabling reliable remote username enumeration through response timing differences. This issue is fixed in version 3.3.0.

Weakness: CWE-203

Which versions are affected by CVE-2026-44332?

3 open source packages ship an affected version, including github.com/gofiber/fiber/v3. It affects 1 product.

Products include Gofiber Fiber.

How do I fix CVE-2026-44332?

Upgrade github.com/gofiber/fiber/v3 to 3.3.0 or later.

Is CVE-2026-44332 being exploited?

There is no known exploitation of CVE-2026-44332 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-2025-66630 Fiber insecurely fallsback in utils.UUIDv4() / utils.UUID() — predictable / zero‑UUID on crypto/rand failure Critical 9.2
• CVE-2025-54801 Fiber Susceptible to Crash via `BodyParser` Due to Unvalidated Large Slice Index in Decoder High 8.7

Sources

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

Also known as GHSA-g5vh-55hw-rxm8, GO-2026-5886, UBUNTU-CVE-2026-44332.