#VU53973 Input validation error in Jetty - CVE-2021-28169

Vulnerability identifier: #VU53973

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-28169

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Jetty
Server applications / Web servers

Vendor: Eclipse

Description

The vulnerability allows a remote attacker to gain access to sensitive information..

The vulnerability exists due to a double decoding issue when parsing URI with certain characters. A remote attacker can send requests to the ConcatServlet and WelcomeFilter and view contents of protected resources within the WEB-INF directory.

Example:

/concat?/%2557EB-INF/web.xml

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Jetty: 9.0.0.v20130308 - 9.4.40.v20210413, 10.0.0 - 11.0.2

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External links
https://github.com/eclipse/jetty.project/security/advisories/GHSA-gwcr-j4wh-j3cq
https://bugs.eclipse.org/bugs/show_bug.cgi?id=573389

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.