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.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00762.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
HAProxy HAProxy unaffected
Version Status Constraints
3.0.0 affected < 3.0.30
3.2.0 affected < 3.2.26
3.3.0 affected < 3.3.17
3.4.0 affected < 3.4.6
3.5-dev affected < 3.5-dev9
HAProxy HAProxy Enterprise Edition unaffected
Version Status Constraints
3.0r1 affected < 3.0r1-362.1441
3.2r1 affected < 3.2r1-378.1259
3.3r1 affected < 3.3r1-377.1005
HAProxy Technologies HAProxy Kubernetes Ingress Controller unaffected
Version Status Constraints
3.2.0 affected < 3.2.17
HAProxy Technologies Kubernetes Ingress Controller Enterprise unaffected
Version Status Constraints
3.2.0 affected < 3.2.17-ee1
3.0 affected < 3.0.16-ee17
1.11 affected < 1.11.14-ee11

No data.

No data.

OpenCVE Enrichment is a feature of OpenCVE that uses AI to automatically link vendors and products to CVEs. Learn more on GitHub.

Vendors Products
Haproxy Subscribe
Haproxy Subscribe
Haproxy Enterprise Subscribe
Kubernetes Ingress Controller Subscribe
Kubernetes Ingress Controller Enterprise Subscribe

Project Subscriptions

Vendors Products
Haproxy Subscribe
Haproxy Subscribe
Haproxy Enterprise Subscribe
Kubernetes Ingress Controller Subscribe
Kubernetes Ingress Controller Enterprise Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://git.haproxy.org/?p=haproxy.git;a=commit;h=077906da140a35873bf451d7e9f67646c9f37c81 cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-110354 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-110354 cve-icon
History

Thu, 22 Oct 2026 12:30:00 +0000

Type Values Removed Values Added
Title Remote Denial of Service via HTTP Chunked Request in HAProxy haproxy: haproxy: Denial of Service via specially crafted HTTP/1.1 chunked request
References
Metrics threat_severity

None

 threat_severity

Important

Thu, 22 Oct 2026 11:00:00 +0000

Type Values Removed Values Added
First Time appeared Haproxy
Haproxy haproxy
Haproxy haproxy Enterprise
Haproxy kubernetes Ingress Controller
Haproxy kubernetes Ingress Controller Enterprise
Vendors & Products Haproxy
Haproxy haproxy
Haproxy haproxy Enterprise
Haproxy kubernetes Ingress Controller
Haproxy kubernetes Ingress Controller Enterprise

Thu, 22 Oct 2026 06:00:00 +0000

Type Values Removed Values Added
Title Remote Denial of Service via HTTP Chunked Request in HAProxy

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'}

Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-10-22T19:10:34.563Z

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

Link: CVE-2026-110354

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

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

Modified: 2026-10-22T19:17:35.660

Link: CVE-2026-110354

cve-icon Redhat

Severity : Important

Publid Date: 2026-10-22T02:46:38Z

Links: CVE-2026-110354 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-22T10:39:14Z

Weaknesses