#VU99358 Inefficient regular expression complexity in REXML - CVE-2024-49761

Vulnerability identifier: #VU99358

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2024-49761

CWE-ID: CWE-1333

Exploitation vector: Network

Exploit availability: No

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

Vendor: rubygems.org

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient input validation when parsing an XML that has many digits between &# and x...; in a hex numeric character reference (&#x...;). A remote attacker can pass specially crafted data to the application and perform regular expression denial of service (ReDos) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

REXML: 3.1.8 - 3.3.8

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External links
http://www.ruby-lang.org/en/news/2024/10/28/redos-rexml-cve-2024-49761/

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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.