Is CVE-2021-33037 being actively exploited?

It is not currently in CISA's KEV catalog. Its EPSS exploitation probability is 75%.

What products does CVE-2021-33037 affect?

Tracked products affected include Apache Tomcat, Debian, Agile Product Lifecycle Management (PLM). Check the version you run to see whether it is affected.

How do I fix CVE-2021-33037?

Apply the vendor fix in your normal patch cycle. Upgrade affected products to a fixed version.

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CVE-2021-33037

Q: What is CVE-2021-33037?

CVE-2021-33037 is a medium-severity software vulnerability (CWE-444) with a CVSS score of 5.3. Apache Tomcat 10.0.0-M1 to 10.0.6, 9.0.0.M1 to 9.0.46 and 8.5.0 to 8.5.66 did not correctly parse the HTTP transfer-encoding request header in some circumstances leading to the possibility to request smuggling when used with a reverse proxy

MEDIUM severity · CVSS 5.3 · CWE-444

5.3CVSS MEDIUM

Summary

Apache Tomcat 10.0.0-M1 to 10.0.6, 9.0.0.M1 to 9.0.46 and 8.5.0 to 8.5.66 did not correctly parse the HTTP transfer-encoding request header in some circumstances leading to the possibility to request smuggling when used with a reverse proxy. Specifically: - Tomcat incorrectly ignored the transfer encoding header if the client declared it would only accept an HTTP/1.0 response; - Tomcat honoured the identify encoding; and - Tomcat did not ensure that, if present, the chunked encoding was the final encoding.

Impact & exploitability

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

Confidentiality impactNone

Integrity impactLow

Availability impactNone

Exploit probability (EPSS)75%

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected products we track (3)

Apache Tomcat Debian Agile Product Lifecycle Management (PLM)

Recommendation

Apply the vendor fix in your normal patch cycle. Open any affected product above for its exact safe version.

CVE-2021-33037

Summary

Impact & exploitability

Affected products we track (3)

Recommendation

Additional information