PR #1419 (login session TTL + redirect-back + connectivity probe) had a
real bug in the server-side ?next= construction:
quote(path, safe='/:@!$&'()*+,;=') keeps ? and & literal, so:
(a) /api/sessions?limit=50&offset=0 round-trips as /api/sessions?limit=50
— the inner & terminates the outer next= value and offset=0 leaks as
a top-level outer query the login page ignores.
(b) An attacker-controlled path with embedded &next=https://evil.com
injects a second top-level next parameter. Browsers parse first-match
(benign), Python parse_qs parses last-match (the evil URL) — the
parser-divergence is a footgun even though _safeNextPath() in login.js
rejects the actual exploit.
Fix: encode the entire path?query blob with safe='/' so ?, &, = all
percent-encode. The outer next then holds exactly one path-with-query
string the browser auto-decodes once.
6 regression tests in test_v050258_opus_followups.py pin round-trip behavior
across simple paths, single-query, multi-param queries, attacker-injection
neutralization, and the SESSION_TTL=30d constant.
Full suite: 3610 passed, 0 failed.
nesquena-hermes
399f12ac96