CVE-2026-64607
Apache HttpComponents Client: Connection Leak on Content-Encoding Decode Error Leads to Pool Exhaustion DoS
Description
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. This issue affects Apache HttpComponents Client: from 5.0-alpha1 through 5.6.2.
INFO
Published Date :
July 31, 2026, 11:17 a.m.
Last Modified :
Aug. 13, 2026, 5:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update Apache HttpComponents Client to version 5.7 or later.
- Ensure response encoding is handled correctly.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-64607.
| URL | Resource |
|---|---|
| https://lists.apache.org/thread/qqfzo3fqcdk4l5496vz95ppvl4ty511q | Mailing List Release Notes |
| http://www.openwall.com/lists/oss-security/2026/08/13/5 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-64607 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-64607
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-64607 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-64607 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Aug. 13, 2026
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2026/08/13/5 -
Initial Analysis by [email protected]
Aug. 10, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:apache:httpclient:*:*:*:*:*:*:*:* versions from (including) 5.0.0 up to (excluding) 5.6.3 Added Reference Type Apache Software Foundation: https://lists.apache.org/thread/qqfzo3fqcdk4l5496vz95ppvl4ty511q Types: Mailing List, Release Notes -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 31, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Added SSVC {'id': 'CVE-2026-64607', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-31T16:24:59.439841Z'} -
New CVE Received by [email protected]
Jul. 31, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Apache Software Foundation', 'product': 'Apache HttpComponents Client', 'versions': [{'status': 'affected', 'version': '5.0-alpha', 'versionType': 'semver', 'lessThanOrEqual': '5.6.2'}], 'packageName': 'org.apache.httpcomponents.client5:httpclient5', 'collectionURL': 'https://repo.maven.apache.org/maven2/', 'defaultStatus': 'unaffected'}] Added Description 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. This issue affects Apache HttpComponents Client: from 5.0-alpha1 through 5.6.2. Added CWE CWE-772 Added Reference https://lists.apache.org/thread/qqfzo3fqcdk4l5496vz95ppvl4ty511q