What is CVE-2026-18311?

CVE-2026-18311 is a medium-severity vulnerability in Readwise Reader, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-09-25.

How severe is CVE-2026-18311?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Readwise Reader

CVE-2026-18311

Readwise Reader for Android contains a cross-site scripting vulnerability due to missing HTML sanitization in its processing of imported document metadata. Attacker-controlled fields such as the author meta tag are inserted into a WebView via innerHTML, enabling stored XSS that executes on synced devices when the malicious document is opened.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-09-25.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Readwise Reader

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

kb.cert.org/vuls/id/699627

Frequently asked questions

What is CVE-2026-18311?: CVE-2026-18311 is a medium-severity vulnerability in Readwise Reader, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-09-25.
How severe is CVE-2026-18311?: Medium severity. CVSS v3 base score is 6.1 out of 10.