Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Fiber's ctx.IsFromLocal() method in github.com/gofiber/fiber/v2 versions before 2.49.2 can be fooled into returning true for remote clients, because it relies on the X-Forwarded-For header. A remote attacker who sends that header with a localhost address can reach resources meant only for local access. Upgrade github.com/gofiber/fiber/v2 to 2.49.2 or later. The github.com/gofiber/fiber package (versions up to 1.14.6) is also listed as affected with no fixed version.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 5.3 | Medium | 3.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0066, the 51st percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:15 UTC First seen by agentprime
- 31 Oct 2026, 14:15 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-3q5p-3558-364f
- OSV: GHSA-3q5p-3558-364f
- github.com/gofiber/fiber/security/advisories/GHSA-3q5p-3558-364f
- nvd.nist.gov/vuln/detail/CVE-2023-41338
- github.com/gofiber/fiber/commit/b8c9ede6efa231116c4bd8bb9d5e03eac1cb76dc
- developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For
- docs.gofiber.io/api/ctx#isfromlocal
- github.com/gofiber/fiber