{"id":"CVE-2023-41338","aliases":["GHSA-3q5p-3558-364f","GO-2023-2052"],"url":"https://o3.security/vulnerability/CVE-2023-41338","summary":"Vulnerability in Ctx.IsFromLocal() in gofiber","details":"### 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","published":"2023-09-08T18:17:18.044Z","modified":"2026-10-28T02:30:36.749401902Z","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"},"epss":{"score":0.00655,"percentile":0.49754,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/gofiber/fiber","fixedVersion":null},{"ecosystem":"Go","name":"github.com/gofiber/fiber/v2","fixedVersion":"2.49.2"}],"fix":{"url":"https://github.com/gofiber/fiber/commit/b8c9ede6efa231116c4bd8bb9d5e03eac1cb76dc","label":"gofiber/fiber@b8c9ede"},"references":[{"type":"WEB","url":"https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For"},{"type":"WEB","url":"https://docs.gofiber.io/api/ctx#isfromlocal"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/41xxx/CVE-2023-41338.json"},{"type":"ADVISORY","url":"https://github.com/gofiber/fiber/security/advisories/GHSA-3q5p-3558-364f"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-41338"},{"type":"FIX","url":"https://github.com/gofiber/fiber/commit/b8c9ede6efa231116c4bd8bb9d5e03eac1cb76dc"},{"type":"PACKAGE","url":"https://github.com/gofiber/fiber"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:30:36.749401902Z"}}