What is CVE-2018-12040?

CVE-2018-12040 is a medium-severity vulnerability in Sensiolabs Symfony, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2018-06-13.

How severe is CVE-2018-12040?

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

XSS in Sensiolabs Symfony

CVE-2018-12040

Reflected Cross-site scripting (XSS) vulnerability in the web profiler in SensioLabs Symfony 3.3.6 allows remote attackers to inject arbitrary web script or HTML via the "file" parameter, aka an _profiler/open?file= URI. NOTE: The vendor states "The XSS ... is in the web profiler, a tool that should never be deployed in production (so, we don't handle those issues as security issues).

Vulnerability class: XSS (Cross-Site Scripting)

Published 2018-06-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.013 (69.6th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 70th percentile — 69.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.013 · newest: 0.013 · change: 0.000

Affected products

Sensiolabs Symfony — versions 3.3.6

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

packetstormsecurity.com/files/148125/SensioLabs-Symfony-3.3.6-Cross-Site-Script… (Exploit, VDB Entry, Third Party Advisory)
www.securityfocus.com/archive/1/542071/100/0/threaded (mailing-list, Exploit, VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2018-12040?: CVE-2018-12040 is a medium-severity vulnerability in Sensiolabs Symfony, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2018-06-13.
How severe is CVE-2018-12040?: Medium severity. CVSS v3 base score is 6.1 out of 10.