CVE-2018-1000844: Retrofit XML External Entity (XXE) Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-j379-9jr9-w5cq
Share
CVSS 9.1
CWE-611
Published
Advisory Summary

CVE-2018-1000844 is a CRITICAL (CVSS 9.1) xml external entity (xxe) vulnerability vulnerability (CWE-611: Improper Restriction of XML External Entity Reference) affecting Retrofit libraries in the Maven ecosystem. The issue involves xml external entity (xxe) vulnerability in square retrofit. Remediation is available by upgrading affected packages to version 2.5.0.

CVE-2018-1000844 at a Glance

CVE Identifier CVE-2018-1000844
GHSA Identifier GHSA-j379-9jr9-w5cq
Severity CRITICAL
CVSS v3.1 Base Score 9.1
CWE Classification CWE-611: Improper Restriction of XML External Entity Reference
Affected Product Retrofit
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2018-1000844

To remediate this vulnerability, upgrade all affected Retrofit dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

com.squareup.retrofit2:retrofit fixed: 2.5.0 
<dependency>
    <groupId>com.squareup.retrofit2</groupId>
    <artifactId>retrofit</artifactId>
    <version>2.5.0</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=com.squareup.retrofit2

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2018-1000844, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=com.squareup.retrofit2

Analyze the terminal output to locate any version of Retrofit in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.5.0), your application is affected.

Note: The mvn dependency:tree -Dincludes=com.squareup.retrofit2 command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-611: Improper Restriction of XML External Entity Reference, where the product processes an xml document that can contain xml entities with uris that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output. In Retrofit, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Square Open Source Retrofit versions prior to commit 4a693c5aeeef2be6c7ecf80e7b5ec79f6ab59437 contain a XML External Entity (XXE) vulnerability in JAXB. An attacker could use this to remotely read files from the file system or to perform SSRF. This vulnerability appears to have been fixed in commit 4a693c5aeeef2be6c7ecf80e7b5ec79f6ab59437.

CVE-2018-1000844 Affected Retrofit Versions

1 component(s)
Fixed Versions:
2.5.0
Product / Package Ecosystem Affected Versions Fixed Version
com.squareup.retrofit2:retrofit
maven/com.squareup.retrofit2/retrofit
Maven
≥ 2.0.0
< 2.5.0
2.5.0

References

NVD — CVE-2018-1000844 NVD
https://nvd.nist.gov/vuln/detail/CVE-2018-1000844
Retrofit Source Repository REPOSITORY
https://github.com/square/retrofit/pull/2735
GitHub Advisory / Wiki ADVISORY
https://github.com/advisories/GHSA-j379-9jr9-w5cq
Retrofit Source Repository REPOSITORY
https://github.com/square/retrofit

Frequently Asked Questions

What is CVE-2018-1000844?
CVE-2018-1000844 is a security vulnerability in Retrofit involving XML External Entity (XXE) vulnerability in Square Retrofit under CWE-611: Improper Restriction of XML External Entity Reference.
Which Retrofit versions are affected?
Affected versions include releases prior to 2.5.0 across affected packages: com.squareup.retrofit2:retrofit.
What version fixes CVE-2018-1000844?
Upgrading to 2.5.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is retrofit affected?
Yes, com.squareup.retrofit2:retrofit is affected in releases prior to 2.5.0. Upgrade your dependency to 2.5.0 or later.
What is the CVSS score of CVE-2018-1000844?
CVE-2018-1000844 has a CVSS v3.1 base score of 9.1 (CRITICAL) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2018-1000844?
CVE-2018-1000844 is classified under CWE-611: Improper Restriction of XML External Entity Reference (The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.).
How can I check Maven dependencies for CVE-2018-1000844?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=com.squareup.retrofit2'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-j379-9jr9-w5cq",
  "modified" : "2022-09-14T22:25:34Z",
  "published" : "2018-12-21T17:48:26Z",
  "aliases" : [ "CVE-2018-1000844" ],
  "summary" : "XML External Entity (XXE) vulnerability in Square Retrofit",
  "details" : "Square Open Source Retrofit versions prior to commit 4a693c5aeeef2be6c7ecf80e7b5ec79f6ab59437 contain a XML External Entity (XXE) vulnerability in JAXB. An attacker could use this to remotely read files from the file system or to perform SSRF. This vulnerability appears to have been fixed in commit 4a693c5aeeef2be6c7ecf80e7b5ec79f6ab59437.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "com.squareup.retrofit2:retrofit"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.0"
      }, {
        "fixed" : "2.5.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2018-1000844"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/square/retrofit/pull/2735"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-j379-9jr9-w5cq"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/square/retrofit"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-611" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-06-16T21:41:45Z",
    "nvd_published_at" : null
  }
}