#VU53588 XML External Entity injection in Nuget - CVE-2021-21658

Vulnerability identifier: #VU53588

Vulnerability risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-21658

CWE-ID: CWE-611

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Nuget
Web applications / Modules and components for CMS

Vendor: Jenkins

Description

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

The vulnerability exists due to insufficient validation of user-supplied XML input in the "Build on NuGet updates" feature. A remote attacker can pass a specially crafted XML code to the affected application and view contents of arbitrary files on the system or initiate requests to external systems.

Successful exploitation of the vulnerability may allow an attacker to view contents of arbitrary file on the server or perform network scanning of internal and external infrastructure.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Nuget: 0.1 - 1.0

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External links
https://www.jenkins.io/security/advisory/2021-05-25/#SECURITY-2340
https://www.openwall.com/lists/oss-security/2021/05/25/3

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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.