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Known exploited vulnerability

CVE-2020-1938

criticalCVSS 3.1 9.8In CISA KEVEPSS 99%Published · Apache

The short answer

CVE-2020-1938 affects Apache Apache Tomcat and is rated critical (CVSS 9.8). CISA added it to the Known Exploited Vulnerabilities catalog on 2022-03-03: attackers are using it, so patch it first. Fixed versions are published for tomcat-embed-core (9.0.31, 8.5.51, 7.0.100).

What it is

When using the Apache JServ Protocol (AJP), care must be taken when trusting incoming connections to Apache Tomcat. Tomcat treats AJP connections as having higher trust than, for example, a similar HTTP connection. If such connections are available to an attacker, they can be exploited in ways that may be surprising. In Apache Tomcat 9.0.0.M1 to 9.0.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99, Tomcat shipped with an AJP Connector enabled by default that listened on all configured IP addresses. It was expected (and recommended in the security guide) that this Connector would be disabled if not required. This vulnerability report identified a mechanism that allowed: - returning arbitrary files from anywhere in the web application - processing any file in the web application as a JSP Further, if the web application allowed file upload and stored those files within the web application (or the attacker was able to control the content of the web application by some other means) then this, along with the ability to process a file as a JSP, made remote code execution possible. It is important to note that mitigation is only required if an AJP port is accessible to untrusted users. Users wishing to take a defence-in-depth approach and block the vector that permits returning arbitrary files and execution as JSP may upgrade to Apache Tomcat 9.0.31, 8.5.51 or 7.0.100 or later. A number of changes were made to the default AJP Connector configuration in 9.0.31 to harden the default configuration. It is likely that users upgrading to 9.0.31, 8.5.51 or 7.0.100 or later will need to make small changes to their configurations.

Severity

9.8 critical

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

Exploited (CISA KEV)

Yes, since Mar 3, 2022

Federal due date Mar 17, 2022

EPSS, next 30 days

99%

Higher than 100% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

What CISA says to do

Apply updates per vendor instructions.

Affected packages and fixed versions

PackageEcosystemFixed inAdvisory
org.apache.tomcat.embed:tomcat-embed-coreMaven9.0.31, 8.5.51, 7.0.100GHSA-c9hw-wf7x-jp9j

Is it in your code? Drop your lockfile into the free vulnerability check, or let vulnerability watch check your repository every day and open the upgrade as a pull request.

Affected products

Apache Tomcat. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2020-1938 being exploited?

Yes. CISA added CVE-2020-1938 to its Known Exploited Vulnerabilities catalog on 2022-03-03, with a federal remediation due date of 2022-03-17.

How do I fix CVE-2020-1938?

Upgrade to a fixed version: org.apache.tomcat.embed:tomcat-embed-core (Maven) 9.0.31 or 8.5.51 or 7.0.100. CISA's required action: Apply updates per vendor instructions.

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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