What is CVE-2019-4520?

CVE-2019-4520 is a high-severity vulnerability in IBM Security Directory Server, classified under Improper Restriction of Excessive Authentication Attempts. CVSS score: 7.5/10. Published 2019-10-02.

How severe is CVE-2019-4520?

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

Vulnerability in IBM Security Directory Server

CVE-2019-4520

IBM Security Directory Server 6.4.0 uses an inadequate account lockout setting that could allow a remote attacker to brute force account credentials. IBM X-Force ID: 165178.

Published 2019-10-02 · 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: 0.022 (82.4th percentile), scored 2026-10-20.

Low probability of exploitation in the next 30 days, but still tracked. 82nd percentile — 82.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.022 · newest: 0.022 · change: 0.000

Affected products

IBM Security Directory Server — versions 6.4.0
IBM Security Directory Server — versions 6.4.0

Weakness classification (CWE)

CWE-307 — Improper Restriction of Excessive Authentication Attempts

References

www.ibm.com/support/pages/node/1077045 (Patch, Vendor Advisory)
exchange.xforce.ibmcloud.com/vulnerabilities/165178 (VDB Entry, vdb-entry, Vendor Advisory)

Frequently asked questions

What is CVE-2019-4520?: CVE-2019-4520 is a high-severity vulnerability in IBM Security Directory Server, classified under Improper Restriction of Excessive Authentication Attempts. CVSS score: 7.5/10. Published 2019-10-02.
How severe is CVE-2019-4520?: High severity. CVSS v3 base score is 7.5 out of 10.