What is CVE-2021-34580?

CVE-2021-34580 is a high-severity vulnerability in Mb Connect Line Mbconnect24, classified under Observable Response Discrepancy. CVSS score: 7.5/10. Published 2021-10-27.

How severe is CVE-2021-34580?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Mb Connect Line Mbconnect24

CVE-2021-34580

In mymbCONNECT24, mbCONNECT24 <= 2.9.0 an unauthenticated user can enumerate valid backend users by checking what kind of response the server sends for crafted invalid login attempts.

Published 2021-10-27 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.010 (62.6th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 62.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: +0.000

Affected products

Mb Connect Line Mbconnect24 — versions 2.9.0
Mb Connect Line Mymbconnect24 — versions 2.9.0
Mbconnectline Mbconnect24
Mbconnectline Mymbconnect24

Weakness classification (CWE)

References

cert.vde.com/en/advisories/VDE-2021-037/ (Third Party Advisory)

Frequently asked questions

What is CVE-2021-34580?: CVE-2021-34580 is a high-severity vulnerability in Mb Connect Line Mbconnect24, classified under Observable Response Discrepancy. CVSS score: 7.5/10. Published 2021-10-27.
How severe is CVE-2021-34580?: High severity. CVSS v3 base score is 7.5 out of 10.