# Readwise Reader Android XSS via poisoned documents

Published: 2026-07-20 · Severity: routine
Canonical: https://vorant.io/reports/5e6cad74-8e5a-55f7-b9a8-a728c6d0670e/readwise-reader-android-xss-via-poisoned-documents

> Three stored XSS flaws in Readwise Reader for Android allow attackers to execute JavaScript through malicious document metadata and SVG markup; version 8.10.1 patches the sanitizer issue.

Readwise Reader for Android versions up to 8.7.2 contain three stored cross-site scripting (XSS) vulnerabilities affecting document rendering. CVE-2026-18311 exploits insufficient HTML escaping in metadata fields like author and title; CVE-2026-18312 targets improper URL escaping in WebView construction for video fallbacks and paywalls; CVE-2026-18320 results from overly permissive SVG/PATH attribute rules in the sanitizer that allow script-capable attributes like onload and onerror.

An attacker who can create or modify documents accessible to the application—either through direct library access or by supplying poisoned content that users save—can inject arbitrary JavaScript that executes within the WebView context. This enables theft of stored documents, credentials, and session tokens. The vulnerabilities are stored, meaning malicious payloads persist in users' libraries and sync across devices.

Version 8.10.1 addresses the sanitizer-wildcard issue (CVE-2026-18320). Users should update immediately and exercise caution when adding content from untrusted sources. The vendor was unreachable at the time of disclosure.

## Mentioned in this report

- Vulnerabilities: CVE-2026-18311, CVE-2026-18312, CVE-2026-18320

Source reporting: https://kb.cert.org/vuls/id/699627

---

This is the free public brief from Vorant Threat Intelligence. When citing, attribute "Vorant" and link https://vorant.io/reports/5e6cad74-8e5a-55f7-b9a8-a728c6d0670e/readwise-reader-android-xss-via-poisoned-documents.
In the app the same report carries its extracted indicators, its detections with Splunk SPL and Microsoft KQL already written, live profiles of the actors and CVEs it names, and the vendor research on the same campaign. Slack alerts fire on the vendors, sectors and countries a reader follows. A new account starts with three days of all of it, no card: https://vorant.io/signup