{"id":"CVE-2023-41338","aliases":["EUVD-2023-2407","GHSA-3q5p-3558-364f","GO-2023-2052"],"status":"published","title":"Vulnerability in Ctx.IsFromLocal() in gofiber","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.","severity":{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00655,"percentile":0.51666,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-670"],"published":"2023-09-08T13:27:21Z","modified":"2026-10-28T02:30:36Z","fixes":[{"ecosystem":"Go","package":"github.com/gofiber/fiber/v2","fixed_in":["2.49.2","2.49.2-0.20230906112033-b8c9ede6efa2"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Go","package":"github.com/gofiber/fiber","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"1.14.6"}]}]},{"source":"ghsa","ecosystem":"Go","package":"github.com/gofiber/fiber/v2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.49.2"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/gofiber/fiber","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"last_affected":"1.14.6"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/gofiber/fiber/v2","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.49.2"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/gofiber/fiber/v2","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.49.2-0.20230906112033-b8c9ede6efa2"}]}]}],"products":[{"vendor":"gofiber","product":"fiber"}],"references":[{"url":"https://github.com/gofiber/fiber/security/advisories/GHSA-3q5p-3558-364f","tags":["x_refsource_CONFIRM","x_transferred","Vendor Advisory","advisory","web"]},{"url":"https://github.com/gofiber/fiber/commit/b8c9ede6efa231116c4bd8bb9d5e03eac1cb76dc","tags":["x_refsource_MISC","x_transferred","Patch","fix","web"]},{"url":"https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For","tags":["x_refsource_MISC","x_transferred","Technical Description","web"]},{"url":"https://docs.gofiber.io/api/ctx#isfromlocal","tags":["x_refsource_MISC","x_transferred","Product","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-41338","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-3q5p-3558-364f"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/41xxx/CVE-2023-41338.json","tags":["advisory"]},{"url":"https://github.com/gofiber/fiber","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2023-41338","title":"Vulnerability in Ctx.IsFromLocal() in gofiber","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. ","status":"published","published":"2023-09-08T18:17:18.044Z","modified":"2024-09-26T14:05:03.642Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-670"],"updated_at":"2026-11-02T14:35:18.88314Z"}],"euvd":[{"id":"EUVD-2023-2407","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. ","status":"published","published":"2023-09-08T18:17:18Z","modified":"2024-09-26T14:05:03Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-03T00:28:10.432496Z"}],"ghsa":[{"id":"GHSA-3q5p-3558-364f","title":"Fiber unauthorized access vulnerability in `ctx.IsFromLocal()`","description":"### 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","status":"published","published":"2023-09-08T13:27:21Z","modified":"2023-11-05T05:01:23Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-670"],"updated_at":"2026-11-02T14:37:13.301199Z"}],"nvd":[{"id":"CVE-2023-41338","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. ","status":"published","published":"2023-09-08T19:15:43.977Z","modified":"2026-06-17T06:21:51.73Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-670"],"updated_at":"2026-11-02T14:08:28.268644Z"}],"osv":[{"id":"CVE-2023-41338","title":"Vulnerability in Ctx.IsFromLocal() in gofiber","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. ","status":"published","published":"2023-09-08T18:17:18.044Z","modified":"2026-10-28T02:30:36.749401902Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-670"],"updated_at":"2026-11-02T15:44:33.244128Z"},{"id":"GHSA-3q5p-3558-364f","title":"Fiber unauthorized access vulnerability in `ctx.IsFromLocal()`","description":"### 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","status":"published","published":"2023-09-08T13:27:21Z","modified":"2026-09-10T03:50:03.184878597Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-670"],"updated_at":"2026-11-02T15:46:36.092962Z"},{"id":"GO-2023-2052","title":"IsFromLocal local address check can be circumvented in github.com/gofiber/fiber/v2","description":"The Ctx.IsFromLocal function can incorrectly report a request as being sent from localhost when the request contains an X-Forwarded-For header containing a localhost IP address.","status":"published","published":"2023-09-12T17:31:22Z","modified":"2024-05-20T16:03:47Z","updated_at":"2026-11-02T15:47:01.185262Z"}]}}