# CVE-2026-18320: Readwise Reader for Android XSS in SVG sanitization

Source: https://junglewise.ai/threats/cve-2026-18320-readwise-reader-for-android-uses-a-sanitize-html-configuration  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-25. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-18320 · Severity: medium · CVSS 6.1 · Published 2026-09-25

Readwise Reader for Android is a reading app that collects and displays articles and documents synchronized across devices. A flaw in the app's HTML sanitizer allows attackers to inject malicious SVG code with event handlers (like onclick or onload) that survive filtering. When a user opens a document with this malicious content, the JavaScript executes within the app, potentially exposing stored documents, credentials, and session tokens.

Technologies: [Readwise Reader for Android](https://junglewise.ai/threats/technologies/reader-for-android). Vendors: [Readwise](https://junglewise.ai/threats/vendors/readwise).

## Quick answers

**Is CVE-2026-18320 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-18320 being exploited in the wild.

**How severe is CVE-2026-18320?** Medium severity, with a CVSS score of 6.1, published 25 September 2026.

**Which products and versions are affected?** Readwise Reader for Android version 8.7.2 and earlier; fixed in 8.10.1.

**Is there a fix for CVE-2026-18320?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-18320 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-18320?** Check whether you run Readwise Reader for Android at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a stored XSS in the article body sanitization component due to a wildcard attribute rule in the sanitize-html configuration that permits all attributes on SVG and PATH elements. This allows script-capable attributes (onload, onerror, etc.) to bypass sanitization. An attacker supplies a malicious document containing crafted SVG markup that is stored in the user's library, synchronized to Android devices, and executed in the Reader WebView when rendered.

## Affected products

- Readwise Reader for Android version 8.7.2 and earlier; fixed in 8.10.1

## Timeline

- 2026-09-25: disclosed

## References

- [https://kb.cert.org/vuls/id/699627](https://kb.cert.org/vuls/id/699627)

## Related threats

- [Readwise Reader for Android stored XSS in WebView URL construction](https://junglewise.ai/threats/cve-2026-18312-readwise-reader-for-android-constructs-urls-in-its-webview-using)
- [Readwise Reader for Android cross-site scripting in document metadata](https://junglewise.ai/threats/cve-2026-18311-readwise-reader-for-android-contains-a-cross-site-scripting)