curl: heap-use-after-free in state.referer when CURLOPT_REFERER replaced or cleared after perform

Calling curleasysetoptcurl, CURLOPTREFERER, ... to replace or clear a previously-set referer after curleasyperform frees the old string via Curlsetstropt lib/setopt.c:87 but leaves data-state.referer.ptr pointing at the freed heap region. curleasygetinfoCURLINFOREFERER and curleasyduphandle then...

curl: libcurl stale CURLOPT_AUTOREFERER leaks a previous request URL to a different origin on a reused easy handle

Summary: libcurl keeps a stale data-state.referer after an HTTP redirect when CURLOPTAUTOREFERER is enabled. Curlhttpfollow stores the previous URL into data-state.referer at lib/http.c:1166-1189, and later requests reuse that value when building Referer: at lib/http.c:2954-2957. In my local...