fix: resolve client IP from the rightmost untrusted X-Forwarded-For entry (backport 2.33) - #27237
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mtojek
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Jul 16, 2026
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Backports #26646 to release/2.33 (Security Support).
A client could spoof its X-Forwarded-For value by prepending a fake IP;
getRemoteAddresstook the leftmost comma-delimited token, so appending proxies (nginx, ALB, Cloudflare) never overrode the spoofed value. This fedhttpmw.RateLimit(per-IP login throttling) and audit logIPAddressfields, enabling rate-limit bypass and audit falsification.This is the security fix tracked in PLAT-258 / coder/security-disclosures#9 (SEC-FC61DF2BF7). It already shipped in mainline (v2.35.0); this PR brings it to the Security Support line.
Clean cherry-pick, no conflicts.
coderd/httpmw/realip_test.gocovers the spoofing scenario.