XSS in PHP

CVE-2026-6735

In PHP versions 8.2.* before 8.2.31, 8.3.* before 8.3.31, 8.4.* before 8.4.21, 8.5.* before 8.5.6, due to improper sanitation of user data, it allows an attacker to compose an URL, which will cause the target to execute arbitrary JavaScript code (XSS) on the target's machine when the target is viewing the PHP-FPM status page.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

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: 0.003 (21.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 21st percentile — 21.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-6735: held from 0.002 to 0.003.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-6735?
CVE-2026-6735 is a medium-severity vulnerability in PHP, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-05-10.
How severe is CVE-2026-6735?
Medium severity. CVSS v3 base score is 6.1 out of 10.