ApostropheCMS: 2nd-order prototype pollution via PATCH leading to single-request persistent DoS

The vulnerability is a single-request persistent DoS by submitting e.g. "PATCH /api/v1/article/<id>" with a valid editor session and body of {"toString.call":"x"}, overwriting the global toString function with value x. Fabian Source Code Location: https://github.com/apostrophecms/apostrophe Affected Packages: - npm:apostrophe, affected <= 4.32.0 CWEs: - CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') CVSS: - CVSS_V4: score 7.1, CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N References: - https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-vmg4-6gfg-83qx - https://nvd.nist.gov/vuln/detail/CVE-2026-71553 - https://github.com/apostrophecms/apostrophe/commit/5a3746aaed49761e171c2cbfe793267c959829fd - https://github.com/advisories/GHSA-vmg4-6gfg-83qx