What is CVE-2026-20797?

CVE-2026-20797 is a medium-severity vulnerability in Copeland Xweb 300d Pro, classified under Out-of-bounds Write. CVSS score: 4.3/10. Published 2026-02-27.

How severe is CVE-2026-20797?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Buffer overflow in Copeland Xweb 300d Pro

CVE-2026-20797

A stack based buffer overflow exists in an API route of XWEB Pro version 1.12.1 and prior, enabling unauthenticated attackers to cause stack corruption and a termination of the program.

Vulnerability class: Buffer Overflow

EPSS: 0.000 (8.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

Affected products

Copeland Xweb 300d Pro — versions 0
Copeland Xweb 500b Pro — versions 0
Copeland Xweb 500d Pro — versions 0
Copeland Xweb_300d_pro
Copeland Xweb_300d_pro_firmware
Copeland Xweb_500b_pro
Copeland Xweb_500b_pro_firmware
Copeland Xweb_500d_pro
Copeland Xweb_500d_pro_firmware

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write
CWE-121 — Stack-based Buffer Overflow

References

ics-cert@hq.dhs.gov (Product)
ics-cert@hq.dhs.gov (US Government Resource, Third Party Advisory)
ics-cert@hq.dhs.gov (Third Party Advisory)

Frequently asked questions

What is CVE-2026-20797?: CVE-2026-20797 is a medium-severity vulnerability in Copeland Xweb 300d Pro, classified under Out-of-bounds Write. CVSS score: 4.3/10. Published 2026-02-27.
How severe is CVE-2026-20797?: Medium severity. CVSS v3 base score is 4.3 out of 10.