What’s Vulnerable › Vulnerabilities

CVE-2023-41338: Vulnerability in Ctx.IsFromLocal() in gofiber

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-09-08 · updated 2026-06-17
• Weakness: CWE-670

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.

Affected products

• gofiber fiber: before 2.49.2 — fixed in 2.49.2

How to fix

Upgrade to a fixed version: gofiber fiber 2.49.2. Check the vendor advisory for mitigations.

References

• https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For
• https://docs.gofiber.io/api/ctx#isfromlocal
• https://github.com/gofiber/fiber/commit/b8c9ede6efa231116c4bd8bb9d5e03eac1cb76dc
• https://github.com/gofiber/fiber/security/advisories/GHSA-3q5p-3558-364f
• https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For
• https://docs.gofiber.io/api/ctx#isfromlocal
• https://github.com/gofiber/fiber/commit/b8c9ede6efa231116c4bd8bb9d5e03eac1cb76dc
• https://github.com/gofiber/fiber/security/advisories/GHSA-3q5p-3558-364f

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