Gogs: Open Redirect in /redirect endpoint via backslash bypass in `IsSameSite`

Gogs is an open source self-hosted Git service. Prior to 0.15.0+dev, an unauthenticated attacker can provide a backslash-containing target to the /redirect endpoint, and similar post-action redirect flows are also affected. internal/urlx/urlx.go IsSameSite validates a normalized form of the target while cmd/gogs/internal/web/web.go getRedirect and other callers use the original value in the Location response. This backslash normalization mismatch lets browsers interpret the Location value as a scheme-relative external URL, allowing links on a trusted Gogs domain to redirect victims to attacker-controlled content for phishing. This vulnerability is fixed in 0.15.0+dev.