GHSA-4j89-2c4f-44c6 Gogs has DoS in rendering issue index pattern

• Go gogs.io/gogs: < 0.14.3 → fixed in 0.14.3

Summary Special template of issue index pattern may cause panic. Details in internal/markup/markup.go ```go link = fmt.Sprintf(`%s`, com.Expand(metas["format"], metas), m) ``` Issue index pattern is rendered to link with `com.Expand`. However, `com.Expand` is not safe. ```go i = strings.Index(template, "}") if s, ok := match[template[:i]]; ok { ``` when `{` is found but `}` not found, i comes to 1, template[:-1] will be called, and then panicked finally, all pages than contains issue index are unavailable. PoC 1. set issue index pattern as follow 2. add a commit which point to an issue in its msg using `#1` above Impact DoS that cause part of pages of the specify repo unavailable.