CVE-2020-1935: Apache Tomcat Potential HTTP Request Smuggling Vulnerability

Q: What is CVE-2020-1935?

CVE-2020-1935 is a security vulnerability in Apache Tomcat involving Potential HTTP request smuggling in Apache Tomcat under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling').

Q: Which Apache Tomcat versions are affected?

Affected versions include releases prior to 7.0.100, 8.5.51, 9.0.31 across affected packages: org.apache.tomcat.embed:tomcat-embed-core, org.apache.tomcat:tomcat.

Q: What version fixes CVE-2020-1935?

Upgrading to 7.0.100, 8.5.51, 9.0.31 (or the latest patched release for your respective branch) resolves the vulnerability.

Q: Is tomcat-embed-core affected?

Yes, org.apache.tomcat.embed:tomcat-embed-core is affected in releases prior to 7.0.100, 8.5.51, 9.0.31. Upgrade your dependency to 7.0.100, 8.5.51, 9.0.31 or later.

Q: Is tomcat affected?

Yes, org.apache.tomcat:tomcat is affected in releases prior to 7.0.100, 8.5.51, 9.0.31. Upgrade your dependency to 7.0.100, 8.5.51, 9.0.31 or later.

Q: What is the CVSS score of CVE-2020-1935?

CVE-2020-1935 has a CVSS v3.1 base score of 4.8 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N.

Q: What CWE is associated with CVE-2020-1935?

CVE-2020-1935 is classified under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') (The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.).

Q: How can I check Maven dependencies for CVE-2020-1935?

Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.apache.tomcat.embed'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

MODERATE

Advisory Identifier: GHSA-qxf4-chvg-4r8r

CVSS 4.8

CWE-444

Published 2020-02-28

Advisory Summary

CVE-2020-1935 is a MODERATE (CVSS 4.8) potential http request smuggling vulnerability (CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')) affecting Apache Tomcat libraries in the Maven ecosystem. The issue involves potential http request smuggling in apache tomcat. Remediation is available by upgrading affected packages to version 7.0.100, 8.5.51, 9.0.31.

CVE-2020-1935 at a Glance

CVE Identifier CVE-2020-1935

GHSA Identifier GHSA-qxf4-chvg-4r8r

Severity MODERATE

CVSS v3.1 Base Score 4.8

CWE Classification CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Affected Product Apache Tomcat

Package Ecosystem Maven

Published Date 2020-02-28

Last Updated 2021-08-19

Security Impact

CVSS: 4.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N).

Attack Vector Network (AV:N)

Attack Complexity High (AC:H)

Privileges Required None (PR:N)

User Interaction None (UI:N)

Scope Unchanged (S:U)

Confidentiality Low (C:L)

Integrity Low (I:L)

Availability None (A:N)

How to Fix CVE-2020-1935

To remediate this vulnerability, upgrade all affected Apache Tomcat dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.apache.tomcat.embed:tomcat-embed-core fixed: 7.0.100

<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-core</artifactId>
    <version>7.0.100</version>
</dependency>

org.apache.tomcat.embed:tomcat-embed-core fixed: 8.5.51

<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-core</artifactId>
    <version>8.5.51</version>
</dependency>

org.apache.tomcat.embed:tomcat-embed-core fixed: 9.0.31

<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-core</artifactId>
    <version>9.0.31</version>
</dependency>

org.apache.tomcat:tomcat fixed: 7.0.100

<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat</artifactId>
    <version>7.0.100</version>
</dependency>

org.apache.tomcat:tomcat fixed: 8.5.51

<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat</artifactId>
    <version>8.5.51</version>
</dependency>

org.apache.tomcat:tomcat fixed: 9.0.31

<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat</artifactId>
    <version>9.0.31</version>
</dependency>

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

mvn dependency:tree -Dincludes=org.apache.tomcat.embed

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2020-1935, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.apache.tomcat.embed

Analyze the terminal output to locate any version of Apache Tomcat in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 7.0.100), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.apache.tomcat.embed command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling'), where the product acts as an intermediary http agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed http requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. In Apache Tomcat, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

In Apache Tomcat 9.0.0.M1 to 9.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99 the HTTP header parsing code used an approach to end-of-line parsing that allowed some invalid HTTP headers to be parsed as valid. This led to a possibility of HTTP Request Smuggling if Tomcat was located behind a reverse proxy that incorrectly handled the invalid Transfer-Encoding header in a particular manner. Such a reverse proxy is considered unlikely.

CVE-2020-1935 Affected Apache Tomcat Versions

6 component(s)

Fixed Versions:

7.0.1008.5.519.0.31

Product / Package	Ecosystem	Affected Versions	Fixed Version
org.apache.tomcat.embed:tomcat-embed-core maven/org.apache.tomcat.embed/tomcat-embed-core	Maven	< 7.0.100	7.0.100
org.apache.tomcat.embed:tomcat-embed-core maven/org.apache.tomcat.embed/tomcat-embed-core	Maven	≥ 8.0.0 < 8.5.51	8.5.51
org.apache.tomcat.embed:tomcat-embed-core maven/org.apache.tomcat.embed/tomcat-embed-core	Maven	≥ 9.0.0 < 9.0.31	9.0.31
org.apache.tomcat:tomcat maven/org.apache.tomcat/tomcat	Maven	< 7.0.100	7.0.100
org.apache.tomcat:tomcat maven/org.apache.tomcat/tomcat	Maven	≥ 8.0.0 < 8.5.51	8.5.51
org.apache.tomcat:tomcat maven/org.apache.tomcat/tomcat	Maven	≥ 9.0.0 < 9.0.31	9.0.31

References

NVD — CVE-2020-1935 NVD

https://nvd.nist.gov/vuln/detail/CVE-2020-1935

Apache Tomcat Security Information SECURITY

https://www.oracle.com/security-alerts/cpuoct2020.html

Apache Tomcat Security Information SECURITY

https://www.oracle.com/security-alerts/cpujul2020.html

Apache Tomcat Security Information SECURITY

https://www.oracle.com/security-alerts/cpujan2021.html

Apache Tomcat Security Information SECURITY

https://www.debian.org/security/2020/dsa-4680

Apache Tomcat Security Information SECURITY

https://www.debian.org/security/2020/dsa-4673

usn.ubuntu.com/4448-1 WEB

https://usn.ubuntu.com/4448-1

Apache Tomcat Security Information SECURITY

https://security.netapp.com/advisory/ntap-20200327-0005

lists.debian.org/debian-lts-announce... WEB

https://lists.debian.org/debian-lts-announce/2020/05/msg00026.html

lists.debian.org/debian-lts-announce... WEB

https://lists.debian.org/debian-lts-announce/2020/03/msg00006.html

lists.apache.org/thread.html/rd547be... WEB

https://lists.apache.org/thread.html/rd547be0c9d821b4b1000a694b8e58ef9f5e2d66db03a31dfe77c4b18@%3Cusers.tomcat.apache.org%3E

lists.apache.org/thread.html/rc31cba... WEB

https://lists.apache.org/thread.html/rc31cbabb46cdc58bbdd8519a8f64b6236b2635a3922bbeba0f0e3743@%3Ccommits.tomee.apache.org%3E

lists.apache.org/thread.html/ra5dee3... WEB

https://lists.apache.org/thread.html/ra5dee390ad2d60307b8362505c059cd6a726de4d146d63dfce1e05e7@%3Cusers.tomcat.apache.org%3E

lists.apache.org/thread.html/r9ce791... WEB

https://lists.apache.org/thread.html/r9ce7918faf347e7aac32be930bf26c233b0b140fe37af0bb294158b6@%3Cdev.tomcat.apache.org%3E

lists.apache.org/thread.html/r80e9c8... WEB

https://lists.apache.org/thread.html/r80e9c8417c77d52c62809168b96912bda70ddf7748f19f8210f745b1@%3Cusers.tomcat.apache.org%3E

lists.apache.org/thread.html/r7bc994... WEB

https://lists.apache.org/thread.html/r7bc994c965a34876bd94d5ff15b4e1e30b6220a15eb9b47c81915b78@%3Ccommits.tomee.apache.org%3E

lists.apache.org/thread.html/r660cd3... WEB

https://lists.apache.org/thread.html/r660cd379afe346f10d72c0eaa8459ccc95d83aff181671b7e9076919@%3Cusers.tomcat.apache.org%3E

lists.apache.org/thread.html/r441c1f... WEB

https://lists.apache.org/thread.html/r441c1f30a252bf14b07396286f6abd8089ce4240e91323211f1a2d75@%3Cusers.tomcat.apache.org%3E

lists.apache.org/thread.html/r127f76... WEB

https://lists.apache.org/thread.html/r127f76181aceffea2bd4711b03c595d0f115f63e020348fe925a916c%40%3Cannounce.tomcat.apache.org%3E

Apache Tomcat Security Information SECURITY

http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00025.html

Frequently Asked Questions

What is CVE-2020-1935?

CVE-2020-1935 is a security vulnerability in Apache Tomcat involving Potential HTTP request smuggling in Apache Tomcat under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling').

Which Apache Tomcat versions are affected?

Affected versions include releases prior to 7.0.100, 8.5.51, 9.0.31 across affected packages: org.apache.tomcat.embed:tomcat-embed-core, org.apache.tomcat:tomcat.

What version fixes CVE-2020-1935?

Upgrading to 7.0.100, 8.5.51, 9.0.31 (or the latest patched release for your respective branch) resolves the vulnerability.

Is tomcat-embed-core affected?

Yes, org.apache.tomcat.embed:tomcat-embed-core is affected in releases prior to 7.0.100, 8.5.51, 9.0.31. Upgrade your dependency to 7.0.100, 8.5.51, 9.0.31 or later.

Is tomcat affected?

Yes, org.apache.tomcat:tomcat is affected in releases prior to 7.0.100, 8.5.51, 9.0.31. Upgrade your dependency to 7.0.100, 8.5.51, 9.0.31 or later.

What is the CVSS score of CVE-2020-1935?

CVE-2020-1935 has a CVSS v3.1 base score of 4.8 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N.

What CWE is associated with CVE-2020-1935?

CVE-2020-1935 is classified under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') (The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.).

How can I check Maven dependencies for CVE-2020-1935?

Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.apache.tomcat.embed'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

Machine-readable OSV JSON OSV v1.5 Schema

Normalized schema output

View Raw JSON

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}

CVSS V3

4.8 MODERATE

Attack Vector Network (AV:N)

Attack Complexity High (AC:H)

Privileges Required None (PR:N)

User Interaction None (UI:N)

Scope Unchanged (S:U)

Confidentiality Low (C:L)

Integrity Low (I:L)

Availability None (A:N)

Vector String

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

Advisory Metadata

Source ID: GHSA-qxf4-chvg-4r8r
Schema Version: 1.4.0
Published: 2020-02-28 01:10
Last Modified: 2021-08-19 19:30
Database Record File: advisories/github-reviewed/2020/02/GHSA-qxf4-chvg-4r8r/GHSA-qxf4-chvg-4r8r.json