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Response snapshot Oct 29, 2026, 18:26 UTC

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VulnerabilityCVE-2026-54458

WWBN AVideo: Unauthenticated Stored DOM Cross-Site Scripting via Per-Client Metadata Broadcast in YPTSocket Plugin

A stored DOM Cross-Site Scripting vulnerability (CWE-79) in the AVideo YPTSocket plugin lets any unauthenticated remote attacker execute arbitrary JavaScript in the authenticated origin of every administrator currently viewing a page that renders the YPTSocket online-users debug panel.

At a glance

Exploited
Not known
Severity
9.6 Critical (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: WWBN/AVideo: 29.1.0. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-8whc-2wmv-ww35 (opens a new tab)

What happened

Summary

A stored DOM Cross-Site Scripting vulnerability (CWE-79) in the AVideo YPTSocket plugin lets any unauthenticated remote attacker execute arbitrary JavaScript in the authenticated origin of every administrator currently viewing a page that renders the YPTSocket online-users debug panel. plugin/YPTSocket/getWebSocket.json.

php issues a signed WebSocket token to any anonymous caller, and MessageSQLiteV2::onOpen at plugin/YPTSocket/MessageSQLiteV2.php lines 91 and 110 reads the attacker-controlled webSocketSelfURI and page_title query parameters from the WebSocket connection URL with no validation.

Both values persist into the in-memory SQLite connections table and broadcast inside the users_id_online array sent to every connected client; on the client, plugin/YPTSocket/script.js::updateSocketUserCard interpolates the broadcast page_title into an HTML template literal that is passed to jQuery $.append(html), which parses attacker bytes into live DOM nodes including with inline event handlers.

Continue reading

Details

plugin/YPTSocket/getWebSocket.json.php issues a WebSocket token to any caller; the only gate is AVideoPlugin::isEnabledByName("YPTSocket"). The token-issuance helper getEncryptedInfo() at plugin/YPTSocket/functions.php:21-24 writes $_REQUEST['webSocketSelfURI'] directly into the per-token state without validation:

// plugin/YPTSocket/functions.php:21-24
if (!empty($_REQUEST['webSocketSelfURI'])) {
 $msgObj->selfURI = $_REQUEST['webSocketSelfURI'];
} else {
 $msgObj->selfURI = getSelfURI();
}

On WebSocket open, MessageSQLiteV2::onOpen reads webSocketSelfURI and page_title from the connection URL query string and persists both verbatim into the in-memory SQLite connections table:

// plugin/YPTSocket/MessageSQLiteV2.php:91 and :110
$client['selfURI'] = $wsocketGetVars['webSocketSelfURI']; // line 91
$client['page_title'] = @utf8_encode(@$wsocketGetVars['page_title']); // line 110

utf8_encode is not an HTML encode. The broadcast helper dbGetUniqueUsers() (plugin/YPTSocket/db.php:288-300) selects both columns without escape and returns them as part of users_id_online, which msgToResourceId() at MessageSQLiteV2.php:444 places in the outbound JSON frame sent to every connected client. JSON encoding escapes " to \" for transport, but the receiving browser's JSON.parse(event.

data) reverses the escape and restores the raw HTML bytes before they reach script.js.

On the client, plugin/YPTSocket/script.js::updateSocketUserCard (lines 638 to 700) interpolates the broadcast page_title into an HTML template literal and passes the result to jQuery $.append(html):

// plugin/YPTSocket/script.js:685-691
if (userData.page_title) textParts.push(userData.page_title);
const finalText = textParts.join(' ');
const html = ` 
 ${finalText}
 `;
$(`#${socketUserDivID} .socketUserPages`).append(html); // sink

jQuery's .append(html) parses the string with the browser HTML parser, building live DOM nodes for any tag the attacker supplied, including with inline event handlers. The browser's load attempt on the attacker-supplied src fails and the inline onerror event handler fires synchronously inside the admin's authenticated origin.

The victim precondition is that the YPTSocket online-users debug panel (#socketUsersURI) is rendered in the admin's DOM. plugin/YPTSocket/footer.php:12 renders the panel when User::isAdmin() && !empty($obj->debugSocket). The debugSocket plugin flag is true by default after enable, so any admin viewing any logged-in AVideo page with the standard YPTSocket footer holds a live broadcast subscription.

Affected product: AVideo (WWBN), YPTSocket plugin Tested version: master branch (snapshot dated 2026-05-22)

PoC

The AVideo deployment must have the YPTSocket plugin enabled (the default after enable) with debugSocket=true (the default), and at least one administrator must currently be viewing a page that loads the YPTSocket footer (any logged-in AVideo page does). The attacker requires only network reachability to getWebSocket.json.php over HTTPS and to the WebSocket TLS port.

Open DevTools Console on any browser tab pointed at the AVideo origin and paste the following one-liner. No authentication and no session cookie are required for the attacker side:

(async () => {
 const PAYLOAD = ' ';
 const r = await fetch('/plugin/YPTSocket/getWebSocket.json.php?webSocketSelfURI=' + encodeURIComponent('/dashboard?x=1'));
 const j = await r.json();
 const u = j.webSocketURL
 + '&webSocketSelfURI=' + encodeURIComponent('/dashboard?x=1')
 + '&page_title=' + encodeURIComponent(PAYLOAD);
 const ws = new WebSocket(u);
 ws.onopen = () => console.log('attacker connected');
 ws.onmessage = e => console.log('attacker frame:', e.data.slice(0, 200));
})();

The payload uses String.fromCharCode to spell its side-effect strings (String.fromCharCode(114,101,100) decodes to red; String.fromCharCode(80,87,78,69,68) decodes to PWNED) so no quote, backtick, or backslash bytes appear in transit. Within one server broadcast cycle, every administrator tab currently rendering the YPTSocket debug panel turns its page background red and changes its browser tab title to PWNED.

Both side-effects are produced by attacker JavaScript executing inside the admin's authenticated AVideo origin.

Impact

This is a stored DOM Cross-Site Scripting vulnerability (CWE-79) in the AVideo YPTSocket plugin. An unauthenticated remote attacker who can reach the YPTSocket endpoints plants the payload by issuing one anonymous HTTP GET to getWebSocket.json.php followed by one anonymous WebSocket frame carrying the malicious page_title.

The attacker JavaScript executes inside the admin's authenticated AVideo origin and can read non-HttpOnly cookies and the CSRF token rendered into the admin dashboard, issue authenticated requests to any admin-only endpoint, exfiltrate the

Affected package ranges reported by GitHub: WWBN/AVideo: < 29.1.0

Scores and how they were measured

CVSS base severity

9.6

Version 3.1As of

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

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-8whc-2wmv-ww35 (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-8whc-2wmv-ww35, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 29). WWBN AVideo: Unauthenticated Stored DOM Cross-Site Scripting via Per-Client Metadata Broadcast in YPTSocket Plugin (CVE-2026-54458). https://kevwire.com/record/CVE-2026-54458

MLA

"WWBN AVideo: Unauthenticated Stored DOM Cross-Site Scripting via Per-Client Metadata Broadcast in YPTSocket Plugin (CVE-2026-54458)." KEVWire, 29 Oct. 2026, kevwire.com/record/CVE-2026-54458.

Chicago

KEVWire. "WWBN AVideo: Unauthenticated Stored DOM Cross-Site Scripting via Per-Client Metadata Broadcast in YPTSocket Plugin (CVE-2026-54458)." Last modified October 29, 2026. https://kevwire.com/record/CVE-2026-54458.

Evidence summary (plain text)

WWBN AVideo: Unauthenticated Stored DOM Cross-Site Scripting via Per-Client Metadata Broadcast in YPTSocket Plugin (Jun 4, 2026).
A stored DOM Cross-Site Scripting vulnerability (CWE-79) in the AVideo YPTSocket plugin lets any unauthenticated remote attacker execute arbitrary JavaScript in the authenticated origin of every administrator currently viewing a page that renders the YPTSocket online-users debug panel.
CVSS 9.6 (version 3.1; evidence as of Oct 29, 2026; https://github.com/advisories/GHSA-8whc-2wmv-ww35).
Sources:
GitHub-reviewed advisory GHSA-8whc-2wmv-ww35: https://github.com/advisories/GHSA-8whc-2wmv-ww35
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: CVE-2026-54458.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 29, 2026, 18:26 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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