{"id":"CVE-2023-41338","aliases":["GHSA-3q5p-3558-364f","GO-2023-2052"],"title":"Fiber unauthorized access vulnerability in `ctx.IsFromLocal()`","summary":"Fiber unauthorized access vulnerability in `ctx.IsFromLocal()`","severity":"medium","cvss":5.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","vendor":"gofiber","product":"github.com/gofiber/fiber","ecosystem":"go","affected":["github.com/gofiber/fiber <= 1.14.6","github.com/gofiber/fiber/v2 < 2.49.2"],"patched":["github.com/gofiber/fiber/v2 2.49.2"],"published":"2023-09-08","updated":"2026-09-10","sourceUpdated":"2026-09-10T03:50:03.184878597Z","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-3q5p-3558-364f","references":[{"url":"https://github.com/gofiber/fiber/security/advisories/GHSA-3q5p-3558-364f"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-41338"},{"url":"https://github.com/gofiber/fiber/commit/b8c9ede6efa231116c4bd8bb9d5e03eac1cb76dc"},{"url":"https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For"},{"url":"https://docs.gofiber.io/api/ctx#isfromlocal"},{"url":"https://github.com/gofiber/fiber"}],"tags":["osv","go"],"epss":0.00655,"epssPercentile":0.49586,"ingestedAt":"2026-09-12T03:13:01.749Z","slug":"CVE-2023-41338","body":"## Overview\n\n### Impact\nThis vulnerability can be categorized as a security misconfiguration. It impacts users of our project who rely on the [ctx.IsFromLocal()](https://docs.gofiber.io/api/ctx#isfromlocal) method to restrict access to localhost requests. If exploited, it could allow unauthorized access to resources intended only for localhost.\n\nIn it's implementation it uses c.IPs():\n\n```go\n// IPs returns a string slice of IP addresses specified in the X-Forwarded-For request header.\n// When IP validation is enabled, only valid IPs are returned.\nfunc (c *Ctx) IPs() []string {\n    return c.extractIPsFromHeader(HeaderXForwardedFor)\n}\n```\n\nThereby, setting `X-Forwarded-For: 127.0.0.1` in a request from a foreign host, will result in true for [ctx.IsFromLocal()](https://docs.gofiber.io/api/ctx#isfromlocal) \n\n### Patches\nThis issue has been patched in `v2.49.2` with commit [b8c9ede6efa231116c4bd8bb9d5e03eac1cb76dc](https://github.com/gofiber/fiber/commit/b8c9ede6efa231116c4bd8bb9d5e03eac1cb76dc)\n\n### Workarounds\nCurrently, there are no known workarounds to remediate this vulnerability without upgrading to the patched version. We strongly advise users to apply the patch as soon as it is released.\n\n### References\nFor further information and context regarding this security issue, please refer to the following resources:\n\n- [Mozilla Developer Network - X-Forwarded-For](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For)\n\n\n\n## Affected packages\n\n- `github.com/gofiber/fiber <= 1.14.6`\n- `github.com/gofiber/fiber/v2 < 2.49.2`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `github.com/gofiber/fiber/v2 2.49.2`","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}