What is CVE-2020-12471?

CVE-2020-12471 is a critical-severity vulnerability in Mono Monox, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2020-04-29.

How severe is CVE-2020-12471?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Deserialization in Mono Monox

CVE-2020-12471

MonoX through 5.1.40.5152 allows remote code execution via HTML5Upload.ashx or Pages/SocialNetworking/lng/en-US/PhotoGallery.aspx because of deserialization in ModuleGallery.HTML5Upload, ModuleGallery.SilverLightUploadModule, HTML5Upload, and SilverLightUploadHandler.

Vulnerability class: Insecure Deserialization

Published 2020-04-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.028 (85.7th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 86th percentile — 85.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.028 · newest: 0.028 · change: 0.000

Affected products

Mono Monox

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

References

github.com/belong2yourself/vulnerabilities/tree/master/MonoX CMS/Remote Code Ex… (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2020-12471?: CVE-2020-12471 is a critical-severity vulnerability in Mono Monox, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2020-04-29.
How severe is CVE-2020-12471?: Critical severity. CVSS v3 base score is 9.8 out of 10.