What is CVE-2026-6730?

CVE-2026-6730 is a critical-severity vulnerability in IBM Concert, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2026-09-23.

How severe is CVE-2026-6730?

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

Buffer overflow in IBM Concert

CVE-2026-6730

IBM Concert 1.0.0 through 3.0.0 is vulnerable to a buffer overflow, caused by improper bounds checking. A local user could overflow the buffer and execute arbitrary code on the system.

Vulnerability class: Buffer Overflow

Published 2026-09-23 · last modified 2026-09-28.

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: 0.003 (23.9th percentile), scored 2026-11-04.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 24th percentile — 23.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000

Affected products

IBM Concert

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

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

Frequently asked questions

What is CVE-2026-6730?: CVE-2026-6730 is a critical-severity vulnerability in IBM Concert, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2026-09-23.
How severe is CVE-2026-6730?: Critical severity. CVSS v3 base score is 9.8 out of 10.