What is CVE-2021-41079?

CVE-2021-41079 is a high-severity vulnerability in Apache Tomcat, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2021-09-16.

How severe is CVE-2021-41079?

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

Is CVE-2021-41079 known to be exploited?

4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Improper input validation in Apache Tomcat

CVE-2021-41079

Apache Tomcat 8.5.0 to 8.5.63, 9.0.0-M1 to 9.0.43 and 10.0.0-M1 to 10.0.2 did not properly validate incoming TLS packets. When Tomcat was configured to use NIO+OpenSSL or NIO2+OpenSSL for TLS, a specially crafted packet could be used to trigger an infinite loop resulting in a denial of service.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published 2021-09-16 · 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:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.072 (94.1th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 94th percentile — 94.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.072 · newest: 0.072 · change: 0.000

Affected products

Apache Tomcat
Apache Software Foundation Tomcat — versions Apache Tomcat 8.5 8.5.0 to 8.5.63, Apache Tomcat 9 9.0.0-M1 to 9.0.43, Apache Tomcat 10 10.0.0-M1 to 10.0.2
NetApp Management Services For Element Software And Hci
Debian Linux — versions 9.0, 10.0, 11.0

Weakness classification (CWE)

Public proof-of-concept exploits

References

lists.apache.org/thread.html/rccdef0349fdf4fb73a4e4403095446d7fe6264e0a58e2df5c… (Mailing List, Vendor Advisory)
lists.debian.org/debian-lts-announce/2021/09/msg00012.html (mailing-list, Mailing List, Third Party Advisory)
security.netapp.com/advisory/ntap-20211008-0005/ (Third Party Advisory)
lists.apache.org/thread.html/rb4de81ac647043541a32881099aa6eb5a23f1b7fd116f713f… (mailing-list)
lists.apache.org/thread.html/r6b6b674e3f168dd010e67dbe6848b866e2acf26371452fdae… (mailing-list)
www.debian.org/security/2021/dsa-4986 (vendor-advisory, Third Party Advisory)

Frequently asked questions

What is CVE-2021-41079?: CVE-2021-41079 is a high-severity vulnerability in Apache Tomcat, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2021-09-16.
How severe is CVE-2021-41079?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2021-41079 known to be exploited?: 4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.