CVE-2026-18320: XSS (CVSS 6.1)

Description

Readwise Reader for Android uses a sanitize-html configuration that permits all attributes on SVG and PATH elements due to a wildcard attribute rule. This configuration fails to remove script-capable attributes such as event handlers (e.g., 'onload', 'onerror'). An attacker could supply a document containing malicious SVG content that survives sanitization and executes script wher rendered in the Reader WebView, resulting in client-side cross-site scripting (XSS).

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CVSS v3.1 Score

6.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0016

Probability of exploitation

0.04%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

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

Frequently Asked Questions

What is CVE-2026-18320? +

Readwise Reader for Android uses a sanitize-html configuration that permits all attributes on SVG and PATH elements due to a wildcard attribute rule. This configuration fails to remove script-capable attributes such as event handlers (e.g., 'onload', 'onerror'). An attacker could supply a document containing malicious SVG content that survives sanitization and executes script wher rendered in the Reader WebView, resulting in client-side cross-site scripting (XSS). It has a CVSS v3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2026-18320? +

CVE-2026-18320 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0016, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-18320? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-18320