What is CVE-2020-13556?

CVE-2020-13556 is a critical-severity vulnerability in Opener Project, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2020-12-11.

How severe is CVE-2020-13556?

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

Buffer overflow in Opener Project

CVE-2020-13556

An out-of-bounds write vulnerability exists in the Ethernet/IP server functionality of EIP Stack Group OpENer 2.3 and development commit 8c73bf3. A specially crafted series of network requests can lead to remote code execution. An attacker can send a sequence of requests to trigger this vulnerability.

Vulnerability class: Buffer Overflow

Published 2020-12-11 · 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: 0.047 (91.5th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 92nd percentile — 91.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.045 · newest: 0.047 · change: +0.002

Affected products

Opener Project — versions 2.3
Eip Stack Group — versions EIP Stack Group OpENer 2.3, EIP Stack Group OpENer development commit 8c73bf3

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

talosintelligence.com/vulnerability_reports/TALOS-2020-1170 (Technical Description, Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2020-13556?: CVE-2020-13556 is a critical-severity vulnerability in Opener Project, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2020-12-11.
How severe is CVE-2020-13556?: Critical severity. CVSS v3 base score is 9.8 out of 10.