Report · CERT/CCAbout CVE-2026-18311Published 25 Sep 2026

VU#699627: Readwise Reader for Android, version 8.7.2, contains multiple XSS vulnerabilities

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Mentioned vulnerabilities

Authoritative record:CVE-2026-18311· Medium 6.1

Not known to be exploited · CVSS 6.1 Medium.

Data as of 13 Nov 2026, 23:53 UTC

CVSS 3.1 base score

6.1Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Changed
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 14 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
ReadwiseReader	Affected >=8.7.2 <=8.10.1	Fixed in–

AI-suggested

Users should update Readwise Reader for Android to version 8.10.1 or later, which includes a patch addressing the sanitizer wildcard issue (CVE-2026-18320). Since the vendor could not be reached for coordinated disclosure, users should monitor for further vendor updates that address all identified vulnerabilities. Additionally, users should exercise caution when adding content from untrusted sources and manually review document metadata before saving articles to reduce exposure to malicious content.

Description

Readwise Reader for Android version 8.7.2 contains three stored cross-site scripting (XSS) vulnerabilities. These flaws allow attackers who can supply malicious documents or metadata to execute arbitrary JavaScript within the app's WebView context. The vulnerabilities arise from insufficient sanitization of document metadata fields, improper escaping of URL metadata, and permissive sanitization rules for SVG markup. Exploitation could compromise user data confidentiality and integrity, including access to stored documents, credentials, and session tokens. A patch addressing one of the issues is available in version 8.10.1. Users are advised to update when possible and exercise caution when adding content from untrusted sources.

Impact

Successful exploitation allows remote attackers to execute arbitrary JavaScript within the Readwise Reader Android app's WebView context by supplying malicious document metadata or SVG markup. This can compromise the confidentiality and integrity of user data, including stored documents, credentials, and session tokens. The vulnerabilities are stored XSS, meaning malicious scripts persist in user libraries and synchronize across devices, increasing exposure risk.

Summary

Three stored XSS vulnerabilities (CVE-2026-18311, CVE-2026-18312, CVE-2026-18320) affect Readwise Reader for Android version 8.7.2. CVE-2026-18311 involves insufficient HTML escaping in header rendering metadata fields like 'doc.author' and 'doc.title', allowing script injection in synchronized documents. CVE-2026-18312 concerns improper escaping of URL metadata used in WebView URL construction for X video fallback and iOS paywall messages, enabling script injection via href attributes. CVE-2026-18320 results from a wildcard attribute rule in the sanitize-html configuration permitting script-capable attributes such as onload and onerror on SVG and PATH elements, allowing malicious SVG markup to execute scripts. These vulnerabilities enable attackers who can craft or modify documents accessible to the app to execute arbitrary JavaScript in the WebView context, potentially compromising user data. The vendor was not reachable for coordination, but version 8.10.1 includes a patch for the sanitizer wildcard issue.

References

kb.cert.org/vuls/id/699627 (opens in a new tab)

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