What is CVE-2021-27578?

CVE-2021-27578 is a medium-severity vulnerability in Apache Zeppelin, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-09-02.

How severe is CVE-2021-27578?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Apache Zeppelin

CVE-2021-27578

Cross Site Scripting vulnerability in markdown interpreter of Apache Zeppelin allows an attacker to inject malicious scripts. This issue affects Apache Zeppelin Apache Zeppelin versions prior to 0.9.0.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-09-02 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.032 (88.2th percentile), scored 2026-10-22.

Low probability of exploitation in the next 30 days, but still tracked. 88th percentile — 88.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.032 · newest: 0.032 · change: 0.000

Affected products

Apache Zeppelin
Apache Software Foundation Zeppelin — versions Apache Zeppelin

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

lists.apache.org/thread.html/r90590aa5ea788128ecc2e822e1e64d5200b4cb92b06707b38… (Mailing List, Vendor Advisory)
www.openwall.com/lists/oss-security/2021/09/02/3 (mailing-list, Mailing List, Third Party Advisory)
lists.apache.org/thread.html/r90590aa5ea788128ecc2e822e1e64d5200b4cb92b06707b38… (mailing-list)
lists.apache.org/thread.html/r31012f2c8e39a5e12e14c1de030012cb8b51c037d953d73b2… (mailing-list)
security.gentoo.org/glsa/202311-04 (vendor-advisory)

Frequently asked questions

What is CVE-2021-27578?: CVE-2021-27578 is a medium-severity vulnerability in Apache Zeppelin, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-09-02.
How severe is CVE-2021-27578?: Medium severity. CVSS v3 base score is 6.1 out of 10.