CVE-2026-64607: Apache HttpComponents Client Denial of Service Vulnerability
MODERATECVE-2026-64607 is a MODERATE (CVSS 5.3) denial of service vulnerability (CWE-772: Missing Release of Resource after Effective Lifetime) affecting Apache HttpComponents Client libraries in the Maven ecosystem. The issue involves connection leak on content-encoding decode error leads to pool exhaustion dos. Remediation is available by upgrading affected packages to version 5.6.3.
CVE-2026-64607 at a Glance
Security Impact
CVSS: 5.3
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).
How to Fix CVE-2026-64607
To remediate this vulnerability, upgrade all affected Apache HttpComponents Client dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
<dependency>
<groupId>org.apache.httpcomponents.client5</groupId>
<artifactId>httpclient5</artifactId>
<version>5.6.3</version>
</dependency>Run the following command in your project directory to verify that all resolved dependencies use the patched release:
mvn dependency:tree -Dincludes=org.apache.httpcomponents.client5How to Check if You Are Affected
To determine whether your Java application is affected by CVE-2026-64607, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:tree -Dincludes=org.apache.httpcomponents.client5Analyze the terminal output to locate any version of Apache HttpComponents Client in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.6.3), your application is affected.
Note: The mvn dependency:tree -Dincludes=org.apache.httpcomponents.client5 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-772: Missing Release of Resource after Effective Lifetime, where the product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed. In Apache HttpComponents Client, 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
CVE-2026-64607 Affected Apache HttpComponents Client Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
org.apache.httpcomponents.client5:httpclient5
|
Maven |
≥ 5.0-alpha1
< 5.6.3
|
5.6.3
|
References
Frequently Asked Questions
What is CVE-2026-64607?
Which Apache HttpComponents Client versions are affected?
What version fixes CVE-2026-64607?
Is httpclient5 affected?
What is the CVSS score of CVE-2026-64607?
What CWE is associated with CVE-2026-64607?
How can I check Maven dependencies for CVE-2026-64607?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-hjcp-jmpx-g3qm",
"modified" : "2026-08-13T18:40:18Z",
"published" : "2026-07-31T12:30:30Z",
"aliases" : [ "CVE-2026-64607" ],
"summary" : "Apache HttpComponents Client: Connection Leak on Content-Encoding Decode Error Leads to Pool Exhaustion DoS",
"details" : "HttpClient based on the classic i/o model fails to correctly release the underlying connection back to the connection manager if it encounters an invalid or unsupported `Content-Encoding` header value in the response message. Please note this defect does not affect HttpClient based on the async i/o model.\n\nThis issue affects Apache HttpComponents Client: from 5.0-alpha1 through 5.6.2.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Maven",
"name" : "org.apache.httpcomponents.client5:httpclient5"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "5.0-alpha1"
}, {
"fixed" : "5.6.3"
} ]
} ]
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-64607"
}, {
"type" : "WEB",
"url" : "https://github.com/apache/httpcomponents-client/commit/55733f4121f7ba26ddf04fe12739d9c15962cb94"
}, {
"type" : "WEB",
"url" : "https://github.com/apache/httpcomponents-client/commit/ebac9512f555c4a355cad3f59ef2db69b597cc97"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/apache/httpcomponents-client"
}, {
"type" : "WEB",
"url" : "https://github.com/apache/httpcomponents-client/releases/tag/rel/v5.6.3"
}, {
"type" : "WEB",
"url" : "https://github.com/apache/httpcomponents-client/releases/tag/rel/v5.7-alpha1"
}, {
"type" : "WEB",
"url" : "https://lists.apache.org/thread/qqfzo3fqcdk4l5496vz95ppvl4ty511q"
}, {
"type" : "WEB",
"url" : "http://www.openwall.com/lists/oss-security/2026/08/13/5"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-772" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-08-13T18:40:18Z",
"nvd_published_at" : "2026-07-31T11:17:11Z"
}
}