What is CVE-2020-7799?

CVE-2020-7799 is a high-severity vulnerability in Fusionauth, classified under Improper Neutralization of Special Elements used in an Expression Language Statement (Expression Language Injection). CVSS score: 7.2/10. Published 2020-01-28.

How severe is CVE-2020-7799?

High severity. CVSS v3 base score is 7.2 out of 10.

Is CVE-2020-7799 known to be exploited?

15 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

RCE in Fusionauth

CVE-2020-7799

An issue was discovered in FusionAuth before 1.11.0. An authenticated user, allowed to edit e-mail templates (Home -> Settings -> Email Templates) or themes (Home -> Settings -> Themes), can execute commands on the underlying operating system by abusing freemarker.template.utility.Execute in the Apache FreeMarker engine that processes custom templates.

Vulnerability class: Log4Shell (CVE-2021-44228)

Published 2020-01-28 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.198 (97.3th percentile), scored 2026-10-02.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 97.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.198 · newest: 0.198 · change: 0.000

Affected products

Fusionauth

Weakness classification (CWE)

CWE-917 — Improper Neutralization of Special Elements used in an Expression Language Statement (Expression Language Injection)

Public proof-of-concept exploits

References

fusionauth.io/docs/v1/tech/release-notes (Exploit, Release Notes, Vendor Advisory)
seclists.org/bugtraq/2020/Jan/39 (mailing-list, Mailing List, Third Party Advisory)
packetstormsecurity.com/files/156102/FusionAuth-1.10-Remote-Command-Execution.h… (VDB Entry, Third Party Advisory)
lab.mediaservice.net/advisory/2020-03-fusionauth.txt (Third Party Advisory)

Frequently asked questions

What is CVE-2020-7799?: CVE-2020-7799 is a high-severity vulnerability in Fusionauth, classified under Improper Neutralization of Special Elements used in an Expression Language Statement (Expression Language Injection). CVSS score: 7.2/10. Published 2020-01-28.
How severe is CVE-2020-7799?: High severity. CVSS v3 base score is 7.2 out of 10.
Is CVE-2020-7799 known to be exploited?: 15 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.