CVE-2026-105862: Payload: Bypassed sanitization of user uploaded SVGs

## Impact A malicious SVG file upload could bypass sanitization, be stored, and execute attacker-controlled JavaScript (XSS) after a user downloads it and opens it. **You are affected if:** - You have a collection configured to upload and allow SVG files which can then be downloaded by users. ## Patches The fix validates SVG content on every upload path and hardens SVG/XML delivery so stored SVGs cannot frame attacker content. Users should upgrade Payload packages to `>= 3.90.0` or `>= 4.0.0-canary.34`. ## Workarounds Disallow SVG uploads, or serve uploaded SVGs as downloads with Content-Disposition: attachment and a strict CSP. These mitigations reduce exposure but do not replace upgrading when the patched release is available.