What is CVE-2019-18211?

CVE-2019-18211 is a high-severity vulnerability in Orckestra C1 Cms, classified under Deserialization of Untrusted Data. CVSS score: 8.8/10. Published 2019-12-23.

How severe is CVE-2019-18211?

High severity. CVSS v3 base score is 8.8 out of 10.

Is CVE-2019-18211 known to be exploited?

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

Deserialization in Orckestra C1 Cms

CVE-2019-18211

An issue was discovered in Orckestra C1 CMS through 6.6. The EntityTokenSerializer class in Composite.dll is prone to unvalidated deserialization of wrapped BinaryFormatter payloads, leading to arbitrary remote code execution for any low-privilege user.

Vulnerability class: Insecure Deserialization

Published 2019-12-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.026 (84.6th percentile), scored 2026-10-03.

Low probability of exploitation in the next 30 days, but still tracked. 85th percentile — 84.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.026 · newest: 0.026 · change: 0.000

Affected products

Orckestra C1 Cms

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

Public proof-of-concept exploits

References

github.com/Orckestra/C1-CMS-Foundation/commits/dev (Patch)

Frequently asked questions

What is CVE-2019-18211?: CVE-2019-18211 is a high-severity vulnerability in Orckestra C1 Cms, classified under Deserialization of Untrusted Data. CVSS score: 8.8/10. Published 2019-12-23.
How severe is CVE-2019-18211?: High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2019-18211 known to be exploited?: 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.