What is CVE-2021-20549?

CVE-2021-20549 is a medium-severity vulnerability in IBM Aix, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-04-27.

How severe is CVE-2021-20549?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in IBM Aix

CVE-2021-20549

IBM Content Navigator 3.0.CD is vulnerable to cross-site scripting. This vulnerability allows users to embed arbitrary JavaScript code in the Web UI thus altering the intended functionality potentially leading to credentials disclosure within a trusted session. IBM X-Force ID: 199167.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-04-27 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.005 (40.1th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 40th percentile — 40.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

www.ibm.com/support/pages/node/6447143 (Vendor Advisory)
exchange.xforce.ibmcloud.com/vulnerabilities/199167 (VDB Entry, vdb-entry, Vendor Advisory)

Frequently asked questions

What is CVE-2021-20549?: CVE-2021-20549 is a medium-severity vulnerability in IBM Aix, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-04-27.
How severe is CVE-2021-20549?: Medium severity. CVSS v3 base score is 5.4 out of 10.