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CVE-2024-55875

CriticalCVSS 9.8 / 10
Published Dec 12, 2024·Last modified Jul 8, 2026
Affected Components(0)

No affected components available

Description

http4k is a functional toolkit for Kotlin HTTP applications. Prior to version 6.50.0.0, there is a potential XXE (XML External Entity Injection) vulnerability when http4k handling malicious XML contents within requests, which might allow attackers to read local sensitive information on server, trigger Server-side Request Forgery and even execute code under some circumstances. The original fix shipped in v5.41.0.0 / v4.50.0.0 closed the documented external-entity attack class (SSRF, local-file disclosure, code execution) by setting ACCESS_EXTERNAL_DTD="", ACCESS_EXTERNAL_SCHEMA="", and isExpandEntityReferences=false on the default DocumentBuilderFactory. A residual gap remained: the parser still accepted documents containing <!DOCTYPE> declarations even though external entity resolution was blocked. This left open billion-laughs-style internal entity expansion DoS attacks against any application using Body.xml() or Document.asXmlDocument() on untrusted XML. v6.50.0.0 closes this residual by adding disallow-doctype-decl=true and FEATURE_SECURE_PROCESSING=true to defaultXmlParsingConfig. Any document containing a <!DOCTYPE> is now rejected at parse time.

Risk Scores
Base Score
9.8

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.

Threat Intelligence
9.3

Active exploitation in the wild has been confirmed. Immediate patching or mitigation is required.

EPSS
1.90%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Proof of Concept

A proof of concept is available for this vulnerability (1 exploit found).

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