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Security Advisories: MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLWd3Y3ItajR3aC1qM2Nx

Jetty Utility Servlets ConcatServlet Double Decoding Information Disclosure Vulnerability

Requests to the ConcatServlet and WelcomeFilter are able to access protected resources within the WEB-INF directory. For example a request to the ConcatServlet with a URI of /concat?/%2557EB-INF/web.xml can retrieve the web.xml file. This can reveal sensitive information regarding the implementation of a web application.

This occurs because both ConcatServlet and WelcomeFilter decode the supplied path to verify it is not within the WEB-INF or META-INF directories. It then uses this decoded path to call RequestDispatcher which will also do decoding of the path. This double decoding allows paths with a doubly encoded WEB-INF to bypass this security check.

Impact

This affects all versions of ConcatServlet and WelcomeFilter in versions before 9.4.41, 10.0.3 and 11.0.3.

Workarounds

If you cannot update to the latest version of Jetty, you can instead deploy your own version of the ConcatServlet and/or the WelcomeFilter by using the code from the latest version of Jetty.

Permalink: https://github.com/advisories/GHSA-gwcr-j4wh-j3cq
JSON: https://advisories.ecosyste.ms/api/v1/advisories/MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLWd3Y3ItajR3aC1qM2Nx
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: almost 3 years ago
Updated: over 1 year ago


CVSS Score: 5.3
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Identifiers: GHSA-gwcr-j4wh-j3cq, CVE-2021-28169
References: Repository: https://github.com/eclipse/jetty.project
Blast Radius: 20.8

Affected Packages

maven:org.eclipse.jetty:jetty-servlets
Dependent packages: 951
Dependent repositories: 8,474
Downloads:
Affected Version Ranges: >= 11.0.0, <= 11.0.2, >= 10.0.0, <= 10.0.2, <= 9.4.40
Fixed in: 11.0.3, 10.0.3, 9.4.41
All affected versions: 10.0.0, 10.0.1, 10.0.2, 11.0.0, 11.0.1, 11.0.2
All unaffected versions: 10.0.3, 10.0.4, 10.0.5, 10.0.6, 10.0.7, 10.0.8, 10.0.9, 10.0.10, 10.0.11, 10.0.12, 10.0.13, 10.0.14, 10.0.15, 10.0.16, 10.0.17, 10.0.18, 10.0.19, 10.0.20, 11.0.3, 11.0.4, 11.0.5, 11.0.6, 11.0.7, 11.0.8, 11.0.9, 11.0.10, 11.0.11, 11.0.12, 11.0.13, 11.0.14, 11.0.15, 11.0.16, 11.0.17, 11.0.18, 11.0.19, 11.0.20