CVE-2026-39410

Hono CVE-2026-39410 involves a cookie handling flaw in getCookie() where a mismatch between browser cookie parsing and JavaScript parse() trim() causes cookies with a non-breaking-space prefix (U+00A0) to shadow or override legitimate cookies. This can bypass __Secure- and __Host- prefix protecti...

Hono: Non-breaking space prefix bypass in cookie name handling in getCookie()

Summary A discrepancy between browser cookie parsing and parse handling allows cookie prefix protections to be bypassed. Cookie names that are treated as distinct by the browser may be normalized to the same key by parse, allowing attacker-controlled cookies to override legitimate ones. Details...