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Vulnerabilities

Threat intelligence · CVE-2021-42340

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.

Published Oct 14, 2021 · catalog updated Jun 17, 2026 · The fix for bug

Last checked Nov 8, 2026. A connected source was read within the last 7 days.

Check this week

CVE-2021-42340 is not in CISA KEV. FIRST estimates a 11.80% chance of exploitation in the next 30 days. Check whether you run The fix for bug.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (The fix for bug).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
11.80%
Remediation
Version ranges on file
Affected products
cpe apache/tomcat

Vulnerabilities in Oracle Products Multiple vulnerabilities have been identified in the multiple Oracle products DoS, directory traversal, and code execution exploits. How it can be Exploited CVE-2022-21273: An unspecified vulnerability exists in Oracle Project Costing due to improper input validation within the Expenses, Currency Override component in Oracle Project Costing. CVE-2021-2351: The remote code execution

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe apache/tomcat10.0.0
  • cpe apache/tomcat10.1.0
  • cpe apache/tomcat< 10.0.12
  • cpe apache/tomcat< 8.5.72
  • cpe apache/tomcat< 9.0.54

How to fix CVE-2021-42340

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-42340 is not in CISA KEV. FIRST estimates a 11.80% chance of exploitation in the next 30 days. Check whether you run The fix for bug.

Which versions are affected?

Compare what you have installed with 10.0.0, 10.1.0, < 10.0.12, < 8.5.72, < 9.0.54. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-772: Missing Release of Resource after Effective Lifetime. EPSS 11.80%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Apache Tomcat security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 8, 2022 · AlienVault OTX

    Detected

    Vulnerabilities in Oracle Products Multiple vulnerabilities have been identified in the multiple Oracle products DoS, directory traversal, and code execution exploits. How it can be Exploited CVE-2022-21273: An unspecified vulnerability exists in Oracle Project Costing due to improper input validation within the Expenses, Currency Override component in Oracle Project Costing. CVE-2021-2351: The re

  2. Jun 17, 2026 · Monitored products — critical

    Updated

    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 OutOfMemoryEr

Sources

  • CVE.orgVulnerability recordCVE-2021-42340

    Official CVE identifier

    cve.org
  • Monitored products — criticalVendor advisoryCVE-2021-42340

    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 OutOfMemoryEr

    nvd.nist.gov
  • AlienVault OTXThreat intelligenceCVE-2021-42340
    otx.alienvault.com

References

Freshness

Last verified in this catalog Nov 8, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgNov 4, 2026
  • Monitored products — criticalNov 3, 2026
  • AlienVault OTXNov 2, 2026