What is CVE-2021-25878?

CVE-2021-25878 is a medium-severity vulnerability in Youphptube, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-11-01.

How severe is CVE-2021-25878?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Youphptube

CVE-2021-25878

AVideo/YouPHPTube 10.0 and prior is affected by multiple reflected Cross Script Scripting vulnerabilities via the videoName parameter which allows a remote attacker to steal administrators' session cookies or perform actions as an administrator.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-11-01 · last modified 2026-07-09.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.009 (56.9th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 57th percentile — 56.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Youphptube

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

af854a3a-2127-422b-91ae-364da2661108 (Product, URL Repurposed, Broken Link)
synacktiv.com (Product)
www.synacktiv.com/sites/default/files/2021-01/YouPHPTube_Multiple_Vulnerabiliti… (Exploit, Vendor Advisory)

Frequently asked questions

What is CVE-2021-25878?: CVE-2021-25878 is a medium-severity vulnerability in Youphptube, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-11-01.
How severe is CVE-2021-25878?: Medium severity. CVSS v3 base score is 6.1 out of 10.