AVideo vulnerable to Stored XSS via html_entity_decode() Reversing xss_esc() Sanitization in Channel About Field

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-33683: 0.18% estimated exploitation activity in the next 30 days; percentile 7.57 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A sanitization order-of-operations flaw in the user profile "about" field allows any registered user to inject arbitrary JavaScript that executes when other users visit their channel page. The xssesc() function entity-encodes input before stripspecifictags() can match dangerous HTML tags, and htmlentitydecode() on output reverses the encoding, restoring the raw malicious HTML. Details Input sanitization in objects/user.php:156: The call order is stripspecifictags(xssesc($about)). The inner xssesc() function (objects/functionsSecurity.php:233) calls htmlspecialchars(): This encodes <scriptalert(1)</script to &lt;script&gt;alert(1)&lt;/script&gt;. Then stripspecifictags() (objects/functions.php:6623-6636) runs regex patterns to remove dangerous tags: But the regex looks for literal <script — it can never match the entity-encoded &lt;script&gt;. The sanitizer is completely neutralized by the encoding that precedes it. Output in view/channelBody.php:239-246: The…

Published by the source

25 Mar 2026, 19:52 UTC

Last modified by the source

25 Mar 2026, 19:52 UTC

Source last checked

26 Oct 2026, 14:39 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-ghx5-7jjg-q2j7

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# Patch Next advisory brief: CVE-2026-33683

Advisory: AVideo vulnerable to Stored XSS via html_entity_decode() Reversing xss_esc() Sanitization in Channel About Field
IDs: CVE-2026-33683, GHSA-ghx5-7jjg-q2j7
Record: https://patchnext.com/advisories/cve-2026-33683 (revision 1, source checked 26 Oct 2026, 14:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist wwbn/avideo: affected <= 26.0

## Suggested inspection (read-only)
- Packagist wwbn/avideo: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on wwbn/avideo.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-ghx5-7jjg-q2j7 (GitHub-reviewed advisory GHSA-ghx5-7jjg-q2j7 lists affected ranges: Packagist wwbn/avideo >=0 <=26.0)

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