CVE-2026-88871: CSRF (CVSS 4.3)

Description

WWBN AVideo through commit c3edcc274c389816d434acadac07ee78eaf330c1 (master, 2026-08-23) contains a cross-site request forgery vulnerability in the CustomizeUser plugin's plugin/CustomizeUser/setSubscribers.json.php endpoint. The script reads users_id and ExtraSubscribers from $_REQUEST and calls User::setExtraSubscribers() without requiring a POST request or a valid CSRF token; autoCSRFGuard() is applied only to POST requests to *.json.php, and the mutation does not pass through ObjectYPT::save()/isUntrustedRequest(), so a cross-origin GET succeeds. An unauthenticated remote attacker who induces a logged-in administrator to load a crafted page (for example an <img> tag pointing at the endpoint) can forge the ExtraSubscribers count displayed on any user's channel. The CustomizeUser plugin is enabled by default, and no patched version was available at the time of reporting.

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CVSS v3.1 Score

4.3

MEDIUM

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

EPSS — Exploit Prediction

0.0014

Probability of exploitation

0.03%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-352 Cross-Site Request Forgery

References

Other References

https://github.com/WWBN/AVideo/security/advisories/GHSA-p9c3-prq7-g8xc https://www.vulncheck.com/advisories/wwbn-avideo-customizeuser-setsubscribers-csrf-via-get https://github.com/WWBN/AVideo/security/advisories/GHSA-p9c3-prq7-g8xc

Frequently Asked Questions

What is CVE-2026-88871? +

WWBN AVideo through commit c3edcc274c389816d434acadac07ee78eaf330c1 (master, 2026-08-23) contains a cross-site request forgery vulnerability in the CustomizeUser plugin's plugin/CustomizeUser/setSubscribers.json.php endpoint. The script reads users_id and ExtraSubscribers from $_REQUEST and calls User::setExtraSubscribers() without requiring a POST request or a valid CSRF token; autoCSRFGuard() is applied only to POST requests to *.json.php, and the mutation does not pass through ObjectYPT::save()/isUntrustedRequest(), so a cross-origin GET succeeds. An unauthenticated remote attacker who induces a logged-in administrator to load a crafted page (for example an <img> tag pointing at the endpoint) can forge the ExtraSubscribers count displayed on any user's channel. The CustomizeUser plugin is enabled by default, and no patched version was available at the time of reporting. It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2026-88871? +

CVE-2026-88871 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0014, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-88871? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-88871