Apache HttpComponents Client: Connection Leak on Content-Encoding Decode Error Leads to Pool Exhaustion DoS
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.apache.httpcomponents.client5:httpclient5 | >= 5.0-alpha1, < 5.6.3 | 5.6.3 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-64607
- https://github.com/apache/httpcomponents-client/commit/55733f4121f7ba26ddf04fe12739d9c15962cb94
- https://github.com/apache/httpcomponents-client/commit/ebac9512f555c4a355cad3f59ef2db69b597cc97
- https://github.com/apache/httpcomponents-client
- https://github.com/apache/httpcomponents-client/releases/tag/rel/v5.6.3
- https://github.com/apache/httpcomponents-client/releases/tag/rel/v5.7-alpha1
- https://lists.apache.org/thread/qqfzo3fqcdk4l5496vz95ppvl4ty511q
- http://www.openwall.com/lists/oss-security/2026/08/13/5
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L- Weakness (CWE)
CWE-772- Platform
- Java / Kotlin (Maven)
- Package
org.apache.httpcomponents.client5:httpclient5- Disclosed
- 31.07.2026
- Updated
- 11.10.2026 13:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-hjcp-jmpx-g3qm - CC BY 4.0
Vulnerability history: org.apache.httpcomponents.client5:httpclient5
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 3
- First → latest
- 04.2025 07.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 2
- Medium 1
Disclosures per year
- 2025: 1
- 2026: 2
-
Apache HttpComponents Client: Connection Leak on Content-Encoding Decode Error Leads to Pool Exhaustion DoS this entry
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