No exploitation reportedFix available

CVE-2021-41079

Q: Is CVE-2021-41079 actively exploited?

Active exploitation of CVE-2021-41079 has not been confirmed. Its EPSS score was 7.2% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-41079?

CVE-2021-41079 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

No exploitation reported by the sources we read.

Published2021-09-16
Fixed in9.0.44 · 8.5.64
WeaknessCWE-20 · CWE-835

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC

2021-09-1615:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-41079?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-41079?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Apache Tomcat

Branch	Affected	Fixed in	Source
9.0	≥ 9.0.0, < 9.0.44	9.0.44	NVD
8.5	≥ 8.5.0, < 8.5.64	8.5.64	NVD
10.0	≥ 10.0.0, ≤ 10.0.2	no fix published	NVD

Debian debian linux

Branch	Affected	Fixed in	Source
9.0	= 9.0	no fix published	NVD
10.0	= 10.0	no fix published	NVD
11.0	= 11.0	no fix published	NVD

Netapp management services for element software and netapp hci

Branch	Affected	Fixed in	Source
—	all versions	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Apache Tomcat to 9.0.44 · 8.5.64

Advisories and patches

lists.apache.orgVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2026-10-08
OpenCVESSVC decisionnone—
NVDCVSS 3.17.5read 2026-10-23
NVDCVSS 2.04.3read 2026-10-23
CNAweakness (CWE)CWE-20read 2026-10-23
NVDweakness (CWE)CWE-835read 2026-10-23
FIRST EPSSEPSS score7.2 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2021-09-16
Last Modified: 2026-10-08
NVD status: Modified

Frequently asked questions

What is CVE-2021-41079?

Is CVE-2021-41079 actively exploited?

Active exploitation of CVE-2021-41079 has not been confirmed. Its EPSS score was 7.2% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-41079?

CVE-2021-41079 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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