CVE-2023-41338 Vulnerability in Ctx.IsFromLocal() in gofiber
Attackers can bypass localhost restrictions in gofiber by spoofing the X-Forwarded-For header, gaining unauthorized access to protected resources.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-41338?
CVE-2023-41338 is a medium-severity authentication bypass vulnerability in gofiber fiber, published on 8 Sep 2023. 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 built in the go language. Versions of gofiber prior to 2.49.2 did not properly restrict access to localhost. This issue impacts users of our project who rely on the `ctx.IsFromLocal` method to restrict access to localhost requests. If exploited, it could allow unauthorized access to resources intended only for localhost. Setting `X-Forwarded-For: 127.0.0.1` in a request from a foreign host, will result in true for `ctx.IsFromLocal`. Access is limited to the scope of the affected process. This issue has been patched in version `2.49.2` with commit `b8c9ede6`. Users are advised to upgrade. There are no known workarounds to remediate this vulnerability without upgrading to the patched version.
Weakness: CWE-670
Which versions are affected by CVE-2023-41338?
5 open source packages ship an affected version, including github.com/gofiber/fiber/v2 and github.com/gofiber/fiber. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/gofiber/fiber/v2 Go | All versions | 2.49.2 |
github.com/gofiber/fiber/v2 Go | All versions | 2.49.2 |
github.com/gofiber/fiber/v2 Go | All versions | 2.49.2-0.20230906112033-b8c9ede6efa2 |
github.com/gofiber/fiber Go | All versions to 1.14.6 | None |
github.com/gofiber/fiber Go | All versions to 1.14.6 | None |
Products include Gofiber Fiber.
How do I fix CVE-2023-41338?
Upgrade github.com/gofiber/fiber/v2 to a fixed version for your release line: 2.49.2 or 2.49.2-0.20230906112033-b8c9ede6efa2.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2023-41338 being exploited?
There is no known exploitation of CVE-2023-41338 in the wild and no public exploit code.
Other vulnerabilities in gofiber fiber
- CVE-2024-38513 Fiber Session Middleware Token Injection Vulnerability
- CVE-2023-45128 CSRF Token Reuse Vulnerability in fiber
- CVE-2024-25124 Fiber has Insecure CORS Configuration, Allowing Wildcard Origin with Credentials
- CVE-2025-66630 Fiber insecurely fallsback in utils.UUIDv4() / utils.UUID() — predictable / zero‑UUID on crypto/rand failure
- CVE-2025-54801 Fiber Susceptible to Crash via `BodyParser` Due to Unvalidated Large Slice Index in Decoder
Sources
Also known as GHSA-3q5p-3558-364f, GO-2023-2052.