vulnerability / NVI-00005029 / Revision 4
AVideo vulnerable to Stored XSS via html_entity_decode() Reversing xss_esc() Sanitization in Channel About Field
OSV carries this publisher advisory for wwbn/avideo. This is an aggregated source copy; consult the original publisher and compare update dates.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
5.4 MEDIUM (3.1)
security-advisories@github.com severity; no combined Null risk score.
5.4 MEDIUM (3.1)
nvd@nist.gov severity; no combined Null risk score.
0.180%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.07527. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
wwbn/avideo
source listedECOSYSTEM: introduced 0; last_affected 26.0
## 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 `xss_esc()` function entity-encodes input before `strip_specific_tags()` can match dangerous HTML tags, and `html_entity_decode()` on output reverses the encoding, restoring the raw malicious HTML. ## Details **Input sanitization** in `objects/user.php:156`: ```php public function setAbout($about) { $this->about = strip_specific_tags(xss_esc($about)); } ``` The call order is `strip_specific_tags(xss_esc($about))`. The inner `xss_esc()` function (`objects/functionsSecurity.php:233`) calls `htmlspecialchars()`: ```php $result = @htmlspecialchars($text, ENT_QUOTES, 'UTF-8'); ``` This encodes `alert(1)` to `<script>alert(1)</script>`. Then `strip_specific_tags()` (`objects/functions.php:6623-6636`) runs regex patterns to remove dangerous tags: ```php $string = preg_replace('/]*>(.*?)/s', $replacement, $string); ``` But the regex looks for literal `` — it can never match the entity-encoded `<script>
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
- NVD lastModified does not establish freshness of every associated CPE record.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-ghx5-7jjg-q2j7 ↗
GitHub Advisory Database via OSV · vendor advisory
Observed . GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.
- CVE-2026-33683 ↗
NIST National Vulnerability Database · official catalog
Observed . This product uses data from the NVD API but is not endorsed or certified by the NVD.
- CVE-2026-33683 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 4 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 3 ·
Source facts changed; compare the preserved prior revision.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.