Description
HAProxy 3 before 3.4.6 allows a remote unauthenticated attacker to cause a denial of service (persistent worker-thread CPU exhaustion) via an HTTP/1.1 chunked request. Although the H1 multiplexer drains the request before closing the stream, the parser repeatedly re-processes the same bytes without making progress. The affected thread stays busy at 100% CPU after timeouts expire and after the client disconnects, and repeated requests can consume all worker threads until the process is restarted.
Published: 2026-10-22
Score: 7.5 High
EPSS: n/a
KEV: No
AI Analysis

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Remediation

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Tracking

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Advisories

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History

Thu, 22 Oct 2026 03:00:00 +0000

Type Values Removed Values Added
Description HAProxy 3 before 3.4.6 allows a remote unauthenticated attacker to cause a denial of service (persistent worker-thread CPU exhaustion) via an HTTP/1.1 chunked request. Although the H1 multiplexer drains the request before closing the stream, the parser repeatedly re-processes the same bytes without making progress. The affected thread stays busy at 100% CPU after timeouts expire and after the client disconnects, and repeated requests can consume all worker threads until the process is restarted.
Weaknesses CWE-835
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-10-22T02:46:38.255Z

Reserved: 2026-10-13T23:22:44.319Z

Link: CVE-2026-110354

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-22T03:16:31.427

Modified: 2026-10-22T03:16:31.427

Link: CVE-2026-110354

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses