High 7.5Published Sep 16, 2021

CVE-2021-41079Apache Tomcat DoS with unexpected TLS packet

Updated under an hour ago (Oct 28, 2026, 5:23 AM ET)

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It affects Apache Software Foundation Apache Tomcat and 3 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for Apache Software Foundation Apache Tomcat

Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-20
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: apache
NVD analysis: Modified
Record last updated: Oct 8, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Apache Software Foundation Apache Tomcat apache_software_foundation:apache_tomcat (from the name)	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	CNA record
apache tomcat apache:tomcat	from 8.5.0 before 8.5.64; from 9.0.0 before 9.0.44; from 10.0.0 through 10.0.2	NVD
debian debian_linux debian:debian_linux	9.0; 10.0; 11.0	NVD
netapp management_services_for_element_software_and_netapp_hci netapp:management_services_for_element_software_and_netapp_hci	all versions	NVD

References

References

https://lists.apache.org/thread.html/rccdef0349fdf4fb73a4e4403095446d7fe6264e0a58e2df5c6799434%40%3Cannounce.tomcat.apache.org%3E	x-refsource-misc
https://lists.debian.org/debian-lts-announce/2021/09/msg00012.html	mailing-list, x-refsource-mlist
https://security.netapp.com/advisory/ntap-20211008-0005/	x-refsource-confirm
https://lists.apache.org/thread.html/rb4de81ac647043541a32881099aa6eb5a23f1b7fd116f713f8ab9dbe%40%3Cdev.tomcat.apache.org%3E	mailing-list, x-refsource-mlist
https://lists.apache.org/thread.html/r6b6b674e3f168dd010e67dbe6848b866e2acf26371452fdae313b98a%40%3Cusers.tomcat.apache.org%3E	mailing-list, x-refsource-mlist
https://www.debian.org/security/2021/dsa-4986	vendor-advisory, x-refsource-debian

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.