How severe is CVE-2020-13934?

CVE-2020-13934 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-13934 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 64% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-13934?

CVE-2020-13934 primarily affects Apache Tomcat. In total, 53 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-13934?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-13934 published?

CVE-2020-13934 was published on 2020-07-14 and last updated on 2026-06-17.

CVE-2020-13934

CVE-2020-13934 is a high-severity vulnerability in Apache Tomcat with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 64% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-401.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 64% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-401
Affected product: Apache Tomcat
Published: 2020-07-14
Last modified: 2026-06-17

Description

An h2c direct connection to Apache Tomcat 10.0.0-M1 to 10.0.0-M6, 9.0.0.M5 to 9.0.36 and 8.5.1 to 8.5.56 did not release the HTTP/1.1 processor after the upgrade to HTTP/2. If a sufficient number of such requests were made, an OutOfMemoryException could occur leading to a denial of service.

Frequently asked questions

What is CVE-2020-13934?: An h2c direct connection to Apache Tomcat 10.0.0-M1 to 10.0.0-M6, 9.0.0.M5 to 9.0.36 and 8.5.1 to 8.5.56 did not release the HTTP/1.1 processor after the upgrade to HTTP/2. If a sufficient number of such requests were made, an OutOfMemoryException could occur leading to a denial of service.
How severe is CVE-2020-13934?: CVE-2020-13934 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-13934 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 64% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-13934?: CVE-2020-13934 primarily affects Apache Tomcat. In total, 53 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-13934?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-13934 published?: CVE-2020-13934 was published on 2020-07-14 and last updated on 2026-06-17.

References

Affected products (53)

cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone10:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone11:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone12:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone13:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone14:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone15:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone16:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone17:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone18:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone19:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone20:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone21:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone22:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone23:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone24:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone25:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone26:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone27:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone5:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone6:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone7:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone8:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:9.0.0:milestone9:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:10.0.0:milestone1:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:10.0.0:milestone2:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:10.0.0:milestone3:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:10.0.0:milestone4:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:10.0.0:milestone5:*:*:*:*:*:*
cpe:2.3:a:apache:tomcat:10.0.0:milestone6:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:a:netapp:oncommand_system_manager:*:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*
cpe:2.3:a:oracle:agile_engineering_data_management:6.2.1.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:agile_plm:9.3.3:*:*:*:*:*:*:*
cpe:2.3:a:oracle:agile_plm:9.3.5:*:*:*:*:*:*:*
cpe:2.3:a:oracle:agile_plm:9.3.6:*:*:*:*:*:*:*

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