---
title: "CVE-2024-55875: http4k has a potential XXE (XML External Entity Injection) vulnerability"
url: https://erroneo.us/security/cve/CVE-2024-55875/
description: "CVE-2024-55875 (org.http4k:http4k-format-xml (Maven)): http4k is a functional toolkit for Kotlin HTTP applications. Prior to version 6.50.0.0, there is a…"
type: vulnerability-record
section: "Security Digest"
date_published: 2024-12-12
date_modified: 2026-06-09
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2024-55875"
kev: false
cvss: 9.8
epss: 0.01905
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2024-55875: http4k has a potential XXE (XML External Entity Injection) vulnerability

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 1.9% , percentile 80: FIRST’s model estimates a 1.9% chance of exploitation activity in the next 30 days, higher than 80% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes org.http4k:http4k-format-xml (Maven) < 6.50.0.0, fixed in 6.50.0.0 . Check your lockfile, including transitive dependencies.

## What it is

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 ACCESSEXTERNALDTD="", ACCESSEXTERNALSCHEMA="", and isExpandEntityReferences=false on the default DocumentBuilderFactory. A residual gap remained: the parser still accepted documents containing 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 FEATURESECUREPROCESSING=true to defaultXmlParsingConfig. Any document containing a is now rejected at parse time.

## Affected packages

- Maven `org.http4k:http4k-format-xml` < 6.50.0.0 → fixed: 6.50.0.0

## Affected products (CVE record)

- http4k http4k: < 6.50.0.0

## Severity

- GitHub_M CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 1.91% probability of exploitation activity in the next 30 days; percentile 80.

## Sources

- [GitHub Advisory GHSA-7mj5-hjjj-8rgw](https://github.com/advisories/GHSA-7mj5-hjjj-8rgw)
- [CVE.org record CVE-2024-55875](https://www.cve.org/CVERecord?id=CVE-2024-55875)
- [NVD entry CVE-2024-55875](https://nvd.nist.gov/vuln/detail/CVE-2024-55875)
- [github.com](https://github.com/http4k/http4k/security/advisories/GHSA-7mj5-hjjj-8rgw)
- [github.com](https://github.com/http4k/http4k/commit/35297adc6d6aca4951d50d8cdf17ff87a8b19fbc)
- [github.com](https://github.com/http4k/http4k/blob/25696dff2d90206cc1da42f42a1a8dbcdbcdf18c/core/format/xml/src/main/kotlin/org/http4k/format/Xml.kt#L42-L46)

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Source page: https://erroneo.us/security/cve/CVE-2024-55875/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt