GHSA-jxfw-x594-9x9m morgan vulnerable to Log Forging via unescaped Unicode line separators

• npm morgan: < 1.12.0 → fixed in 1.12.0

Impact Morgan writes attacker-controlled request data to the access log through its tokens. The 1.11.0 fix neutralizes C0 control characters, DEL, and backslash, but it does not escape the Unicode line separators `U+0085` (NEL), `U+2028` (LINE SEPARATOR), or `U+2029` (PARAGRAPH SEPARATOR). These code points are reachable through several tokens, including the request URL (`:url`), request headers such as `:user-agent` and `:referrer`, arbitrary `:req[header]` values, and the Basic auth username (`:remote-user`). NEL is valid `obs-text` in HTTP header values, so an attacker can place it in an ordinary request header. When such a value is logged, the raw code points survive into the emitted access-log record, and downstream ECMAScript-aware or Unicode-aware log processing splits the single physical record into multiple logical records. This allows an attacker to forge log entries. The built-in `combined`, `common`, `default`, and `short` formats are affected, as well as any custom format. This is an incomplete fix of CVE-2026-5078. Patches Users should upgrade to version 1.12.0. Workarounds None. The affected values include the request URL and request headers, which are core to access logging, so there is no practical format-based mitigation. Upgrade to 1.12.0.