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CVE-2021-41079 Apache Tomcat

Affected softwareApache Tomcat
Severity7.5 High CVSS 3.1 2 scores
Fixed in10.0.4, 9.0.44, 8.5.64
WeaknessImproper input validation (CWE-20)
Published16 Sep 2021
Updated8 Oct 2026

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.

CWE-835

Exploitation status

No public exploit

No exploit has been reported in the sources we check. Published 5 years ago.

  • CISA KEV not listed
  • VulnCheck KEV not listed
  • CISA Vulnrichment exploitation: none
  • Indexed PoC none indexed
  • EPSS 7.2% chance in 30 days

Waratek protection

No exploit published

Within Waratek scope. In the sources we check, nobody has published exploit code for this CVE or reported it being exploited.

A public code fix exists: apache/tomcat 34115fb.

  • Protection none
  • Action unverified
  • Review automated Upstream data
  • Record active
Decided by Exploit code for this candidate, published in a reviewed catalogue or a GitHub repository with 5 or more stars, or in use per CISA or VulnCheck; not only a CISA verdict, a forecast, or nothing at all
Finding This CVE is not listed in CISA KEV or VulnCheck KEV, CISA Vulnrichment records no active exploitation, no reviewed exploit catalogue carries an entry for it, and no GitHub PoC repository for it has 5 or more stars. Nobody has published exploit code worth tracing, so it is not a candidate for a rule ahead of the ones where somebody has; an upstream fix path does exist, so the remediation half of the candidacy still holds. This is a statement about what has been published, not about whether the defect is reachable or serious.

CVSS

7.5 HIGH v3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H 2 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

VersionScoreBandVectorAssignerType
CVSS 3.1 7.5 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H NVD Primary published
CVSS 2.0 4.3 none AV:N/AC:M/Au:N/C:N/I:N/A:P NVD Primary

Affected software and releases

Oracle advisories

AdvisoryTypeQuarterProducts Oracle names in its risk matrix
Oracle Critical Patch Update April 2025 ↗ CPU 2025-Q2 Oracle Autonomous Health Framework / Trace File Analyzer (Apache Tomcat) (23.8.0-23.11.0, 24.1.0-24.11.0, 25.1.0, 25.2.0)

Oracle components and versions

FamilyComponentVersions, as Oracle lists themRead as
Oracle Autonomous Health Framework Trace File Analyzer (Apache Tomcat) 23.8.0-23.11.0, 24.1.0-24.11.0, 25.1.0, 25.2.0 25.1.0 · 25.2.0

Maven packages

Affected and fixed versions, from OSV.dev
PackageIntroducedFixedLast affected
org.apache.tomcat:tomcat 10.0.0 10.0.4 unbounded
org.apache.tomcat:tomcat 9.0.0 9.0.44 unbounded
org.apache.tomcat:tomcat 8.5.0 8.5.64 unbounded

Products and versions

4 products, 10 version entries
SourceVendorProductSchemeAffected versions
nvd apache tomcat generic ≥ 8.5.0 and < 8.5.64 · ≥ 9.0.0 and < 9.0.44 · ≥ 10.0.0 and ≤ 10.0.2
nvd debian debian linux generic 9.0 · 10.0 · 11.0
nvd netapp management services for element software and netapp hci generic any version
osv org.apache.tomcat tomcat generic ≥ 8.5.0 and < 8.5.64 · ≥ 9.0.0 and < 9.0.44 · ≥ 10.0.0 and < 10.0.4

References

URLTags
https://github.com/apache/tomcat/commit/34115fb3c83f6cd97772232316a492a4cc5729e0 WEB
https://github.com/apache/tomcat PACKAGE
https://lists.apache.org/thread.html/r6b6b674e3f168dd010e67dbe6848b866e2acf26371452fdae313b98a@%3Cusers.tomcat.apache.org%3E WEB
https://lists.apache.org/thread.html/rb4de81ac647043541a32881099aa6eb5a23f1b7fd116f713f8ab9dbe@%3Cdev.tomcat.apache.org%3E WEB
https://lists.apache.org/thread.html/rccdef0349fdf4fb73a4e4403095446d7fe6264e0a58e2df5c6799434%40%3Cannounce.tomcat.apache.org%3E WEB
https://lists.debian.org/debian-lts-announce/2021/09/msg00012.html WEB
https://security.netapp.com/advisory/ntap-20211008-0005 WEB
https://www.debian.org/security/2021/dsa-4986 WEB
https://lists.apache.org/thread.html/r6b6b674e3f168dd010e67dbe6848b866e2acf26371452fdae313b98a%40%3Cusers.tomcat.apache.org%3E
https://lists.apache.org/thread.html/rb4de81ac647043541a32881099aa6eb5a23f1b7fd116f713f8ab9dbe%40%3Cdev.tomcat.apache.org%3E

Timeline

Published2021-09-16By the CVE Program.
NVD record modified2026-10-08NVD's own last-modified date for this record.