HOMEVULNERABILITIESCVE-2021-42340
HIGH

CVE-2021-42340

CWE-772Published: October 14, 2021· Updated: Jun 17, 2026

7.5
CVSS v3.1

Official Description

The fix for bug 63362 present in Apache Tomcat 10.1.0-M1 to 10.1.0-M5, 10.0.0-M1 to 10.0.11, 9.0.40 to 9.0.53 and 8.5.60 to 8.5.71 introduced a memory leak. The object introduced to collect metrics for HTTP upgrade connections was not released for WebSocket connections once the connection was closed. This created a memory leak that, over time, could lead to a denial of service via an OutOfMemoryError.

NVD Source

Technical Analysis

CVE-2021-42340 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

Apache1 product(s)
tomcat
Debian1 product(s)
debian linux
netapp2 product(s)
hcimanagement services for element software
Oracle14 product(s)
agile engineering data managementbig data spatial and graphcommunications diameter signaling routerhospitality cruise shipboard property management systemmanaged file transfermiddleware common libraries and toolspayment interfaceretail customer insightsretail data extractor for merchandisingretail eftlinkretail financial integrationretail store inventory management+2
Source: NVD CPE · 31 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://www.oracle.com/security-alerts/cpuapr2022.html
PATCHhttps://www.oracle.com/security-alerts/cpujan2022.html
PATCHhttps://www.oracle.com/security-alerts/cpujul2022.html
PATCHhttps://www.oracle.com/security-alerts/cpuapr2022.html
PATCHhttps://www.oracle.com/security-alerts/cpujan2022.html
PATCHhttps://www.oracle.com/security-alerts/cpujul2022.html
ADVISORYhttps://kc.mcafee.com/corporate/index?page=content&id=SB10379
ADVISORYhttps://lists.apache.org/thread.html/r83a35be60f06aca2065f188ee542b9099695d57ced2e70e0885f905c%40%3Cannounce.tomcat.apache.org%3E
ADVISORYhttps://security.gentoo.org/glsa/202208-34
ADVISORYhttps://security.netapp.com/advisory/ntap-20211104-0001/
ADVISORYhttps://www.debian.org/security/2021/dsa-5009
ADVISORYhttps://kc.mcafee.com/corporate/index?page=content&id=SB10379
ADVISORYhttps://lists.apache.org/thread.html/r83a35be60f06aca2065f188ee542b9099695d57ced2e70e0885f905c%40%3Cannounce.tomcat.apache.org%3E
ADVISORYhttps://security.gentoo.org/glsa/202208-34
ADVISORYhttps://security.netapp.com/advisory/ntap-20211104-0001/
ADVISORYhttps://www.debian.org/security/2021/dsa-5009

All References (18)

→
https://kc.mcafee.com/corporate/index?page=content&id=SB10379Third Party Advisory
→
https://lists.apache.org/thread.html/r8097a2d1550aa78e585fc77e602b9046e6d4099d8d132497c5387784%40%3Ccommits.myfaces.apache.org%3E
→
https://lists.apache.org/thread.html/r83a35be60f06aca2065f188ee542b9099695d57ced2e70e0885f905c%40%3Cannounce.tomcat.apache.org%3EMailing List · Vendor Advisory
→
https://security.gentoo.org/glsa/202208-34Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20211104-0001/Third Party Advisory
→
https://www.debian.org/security/2021/dsa-5009Third Party Advisory
→
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch · Third Party Advisory
→
https://www.oracle.com/security-alerts/cpujan2022.htmlPatch · Third Party Advisory
→
https://www.oracle.com/security-alerts/cpujul2022.htmlPatch · Third Party Advisory
→
https://kc.mcafee.com/corporate/index?page=content&id=SB10379Third Party Advisory
→
https://lists.apache.org/thread.html/r8097a2d1550aa78e585fc77e602b9046e6d4099d8d132497c5387784%40%3Ccommits.myfaces.apache.org%3E
→
https://lists.apache.org/thread.html/r83a35be60f06aca2065f188ee542b9099695d57ced2e70e0885f905c%40%3Cannounce.tomcat.apache.org%3EMailing List · Vendor Advisory
→
https://security.gentoo.org/glsa/202208-34Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20211104-0001/Third Party Advisory
→
https://www.debian.org/security/2021/dsa-5009Third Party Advisory

Quick Facts

CVE IDCVE-2021-42340
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-772
CISA KEVNo
Affected4 vendor(s)
PublishedOct 14, 2021

Related CVEs (CWE-772)

CVE-2017-15032
9.8
CVE-2020-12134
9.8
CVE-2017-11641
9.8
CVE-2017-14138
9.8
CVE-2017-12669
8.8
CVE-2017-12641
8.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-42340 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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