What is CVE-2026-6721?

CVE-2026-6721 is a critical-severity vulnerability in IBM Concert, classified under OS Command Injection. CVSS score: 9.8/10. Published 2026-09-23.

How severe is CVE-2026-6721?

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

RCE in IBM Concert

CVE-2026-6721

IBM Concert 1.0.0 through 3.0.0 allows an unauthenticated remote attacker can supply specially crafted input that is incorporated into OS commands, resulting in arbitrary command execution on the underlying system. Successful exploitation allows remote code execution with the privileges of the affected application.

Vulnerability class: Command Injection (OS Command Injection)

Published 2026-09-23.

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

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

IBM Concert

Weakness classification (CWE)

CWE-78 — OS Command Injection

References

www.ibm.com/support/pages/node/7288830 (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-6721?: CVE-2026-6721 is a critical-severity vulnerability in IBM Concert, classified under OS Command Injection. CVSS score: 9.8/10. Published 2026-09-23.
How severe is CVE-2026-6721?: Critical severity. CVSS v3 base score is 9.8 out of 10.