BuddyPress Chat Plugin Allows Stored XSS via Message Injection

The BuddyPress Instant Chat WordPress plugin through 1.6 does not check that the sender of a chat message belongs to the conversation it is being added to, nor does it escape message content before outputting it back, allowing unauthenticated users to store arbitrary web scripts that will execute in the session of any member who later views that conversation.

Casky was already ahead

This CVE exploits attack patterns that Casky's 323matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

The BuddyPress Instant Chat WordPress plugin through version 1.6 contains a critical stored cross-site scripting (XSS) vulnerability that combines two security failures: inadequate access controls on message insertion and missing output encoding. Unauthenticated attackers can inject malicious JavaScript into chat conversations without verification of membership, and because the plugin fails to sanitize message content before display, the scripts execute in the browsers of legitimate users viewing those conversations. This affects any WordPress installation running the vulnerable plugin, potentially compromising site members' sessions, credentials, and sensitive data—particularly dangerous given chat plugins' typical use for private communications.

Casky's 323 mapped skills detect this attack pattern by analyzing behaviors across MITRE ATT&CK's Initial Access (TA0001) and Persistence (TA0043) tactics. The platform's Claude AI-powered reasoning identifies the reconnaissance phase where attackers probe conversation endpoints for authorization checks, followed by the injection of stored payloads that achieve persistence across user sessions. Practitioners using Casky would observe findings highlighting: (1) anomalous unauthenticated requests to chat message endpoints lacking proper membership validation, (2) message payloads containing script tags or event handlers bypassing output encoding, and (3) repeated access patterns consistent with payload testing. The extended reasoning capability connects these signals to the underlying CWE-79 weakness, enabling teams to prioritize remediation and implement compensating controls like Content Security Policy headers while awaiting plugin updates.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

323 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-87764.

Abuse of Public-Facing API: Mobile API Abuse

mobile security · low

Run

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

MITRE ATT&CK Techniques

TA0001 TA0043

Investigate the attack patterns behind CVE-2026-87764

Casky has 323 skills that investigate the attack patterns behind CVE-2026-87764. Run one and get CVSS-scored findings in 3 minutes.

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