Is CVE-2021-42340 in the CISA KEV catalog?

No. CVE-2021-42340 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-42340?

CVE-2021-42340 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2021-42340?

CVE-2021-42340 has an EPSS score of 11.00% (95th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-42340?

Upgrade tomcat9 on debian 11 to 9.0.43-2~deb11u3 or later.

CVE & CISA-KEV Catalog

CVE-2021-42340

HIGHEPSS 95th pctl

7.5

CVSS v3

NVD

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.

CWE-772

How to fix

Remediation Available

tomcat9Debian

Fixed in:9.0.43-2~deb11u3CVE-2021-42340

Fixed in:9.0.54-1CVE-2021-42340

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

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

Exploit Intelligence

11.00%probability of exploitation in 30 days

95thpercentile

Very high risk: more likely to be exploited than 95% of all known CVEs.

References

Patch3

Vendor Advisory1

lists.apache.org

Third-Party Advisory4

Other references1

lists.apache.org

Related Vulnerabilities

Other CWE-772 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2003-0132	Medium	5.0	86%	-	Fix
CVE-2017-14495	High	7.5	84%	-	Fix
CVE-2021-22883	High	7.5	77%	-	Fix
CVE-2024-2398	High	8.6	36%	-	Fix
CVE-2020-9375	High	7.5	28%	-	-
CVE-1999-1127	High	7.5	18%	-	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.