---
id: "bug-1948"
status: "fixed"
status_updated: "2026-10-10"
status_note: ""
component: "apiserver"
severity: "security"
timestamp: "2026-10-10T08:15:06Z"
last_seen: "2026-10-10T08:15:06Z"
occurrences: 1
files: ["src/frontend/apiserver/router/routers.go"]
tags: ["apiserver", "security", "whitelist"]
related: []
fix_commits: ["c4c63f11"]
gitea_issue: 379
gitea_synced_status: "fixed"
gitea_synced_hash: "c922e7fd47f6"
---

# bug-1948: apiserver trusts X-Forwarded-For from any client, so IP whitelist and JWT IP binding can be spoofed

## Description
**Observed:** (source reading, `.kiro/reviews/project-gap-review-2026-10-10.md` (P0); to be confirmed by a failing test before the fix)
The router uses `gin.Default()` (`router/routers.go:19`) and never calls `SetTrustedProxies`, so `ClientIP()` honours `X-Forwarded-For` from any peer.

**Expected:** Forwarded headers are only honoured from configured trusted proxies.
**Impact:** Security: a client can claim any IP and bypass the IP whitelist and the IP bound into its JWT.
**Found by:** review: `.kiro/reviews/project-gap-review-2026-10-10.md` (P0)
## Environment
- OS: no /etc/os-release; Docker container; NixOS kernel; kernel Linux 6.18.33 x86_64
- libc: glibc 2.42-47 (interpreter /nix/store/wb6rhpznjfczwlwx23zmdrrw74bayxw4-glibc-2.42-47/lib/ld-linux-x86-64.so.2)
- Toolchain: gcc (GCC) 15.2.0, meson 1.9.1
- Build: asan (xce.build)
- Code: scheduler-framework @ 94472ee3-dirty
- Deployment: any (found by source reading; the failing test that confirms it is named in Verification)

## Reproduction
1. Send a request with `X-Forwarded-For: <whitelisted IP>` from a non-whitelisted host.
2. It passes the whitelist.
- Frequency: deterministic (by code reading; confirmed by the RED test of the fix)
- Evidence: the code sites quoted in Description; no logs kept.
## Root cause
`router.Router()` used `gin.Default()` without `SetTrustedProxies`, so `ClientIP()` honoured X-Forwarded-For from any peer.

## Fix
New `app.yaml` option `security.trusted_proxies` (IP/CIDR, default empty = none), validated at startup; `Router()` passes it to `SetTrustedProxies` (falls back to none if invalid); schema and nginx samples documented.

## Verification
- Test: `TestRouter_IgnoresForwardedForByDefault` (`router/routers_test.go`, real `Router()`): RED `non-whitelisted peer spoofing X-Forwarded-For: status = 200, want 403`, GREEN after; plus `TestRouter_HonoursForwardedForFromTrustedProxy`, `TestResolveTrustedProxies`.
- Suites: `xce-build.sh all asan xce.build --incremental` on the merged branch, 2026-10-10: all C suites Ok 155 / Fail 0, frontend Go unit tests ok, xceadmin tests ok; apiserver `CGO_ENABLED=0 go test ./...` (incl. middleware, router, cmd) ok
- Live: n/a: unit/fixture-level verification only; no live deployment was run (follow-up)

## References
- Fix commit: `c4c63f11` (on `scheduler-framework`; worker-branch original in the merge)
- Review: `.kiro/reviews/project-gap-review-2026-10-10.md`