CVE-2026-64607

Apache HttpComponents Client: Connection Leak on Content-Encoding Decode Error Leads to Pool Exhaustion DoS

MEDIUM
5.3
CVSS Score
Published: July 31, 2026 at 10:12 AM UTC
Updated: October 23, 2026 at 11:10 PM UTC
1 product affected across 1 vendorHttpclient

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.0.0 ≤ v < 5.6.35.0-alpha
Affected range stops below 5.6.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

Vendor AdvisoryMailing ListRelease Notes
Source: cverecord
https://lists.apache.org/thread/qqfzo3fqcdk4l5496vz95ppvl4ty511q
Source: af854a3a-2127-422b-91ae-364da2661108
http://www.openwall.com/lists/oss-security/2026/08/13/5

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-772

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