---
id: CVE-2026-110353
title: >-
  HAProxy 3.2 before 3.4.6 allows a remote unauthenticated attacker to cause a
  denial of service (worker-thread CPU exhaustion) via a truncated HTTP/2 PING
  frame
summary: >-
  HAProxy 3.2 before 3.4.6 allows a remote unauthenticated attacker to cause a
  denial of service (worker-thread CPU exhaustion) via a truncated HTTP/2 PING
  frame. h2c_handle_ping in src/mux_h2.c does not check for a short read, unlike
  the …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-252
vendor: HAProxy
product: HAProxy
affected:
  - HAProxy >= 3.2.0 < 3.2.26
  - HAProxy >= 3.3.0 < 3.3.17
  - HAProxy >= 3.4.0 < 3.4.6
  - HAProxy >= 3.5-dev < 3.5-dev9
  - enterprise_edition >= 3.2.0r1 < 3.2r1-378.1259
  - enterprise_edition >= 3.3.0r1 < 3.3r1-377.1005
  - kubernetes_ingress_controller >= 3.2.0 < 3.2.17
  - kubernetes_ingress_controller_enterprise >= 3.2.0 < 3.2.17-ee1
  - kubernetes_ingress_controller_enterprise >= 3.0 < 3.0.16-ee17
  - kubernetes_ingress_controller_enterprise >= 1.11 < 1.11.14-ee11
published: '2026-10-22'
updated: '2026-10-22'
sourceUpdated: '2026-10-22T02:53:33.198Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-110353'
references:
  - url: >-
      https://git.haproxy.org/?p=haproxy.git;a=commit;h=cec63e95f62a7412484f1134f5aa227e5b7e1466
tags:
  - cve.org
ingestedAt: '2026-10-22T03:25:15.657Z'
---

## Overview

HAProxy 3.2 before 3.4.6 allows a remote unauthenticated attacker to cause a denial of service (worker-thread CPU exhaustion) via a truncated HTTP/2 PING frame. h2c_handle_ping in src/mux_h2.c does not check for a short read, unlike the other H2 frame handlers. Because the incomplete frame cannot be processed, its data is never consumed, and the H2 multiplexer tasklet is repeatedly woken by that pending data without making progress. The CPU spins until timeout http-request closes the connection, and an attacker opening many such connections can sustain high CPU usage.

## Affected

- `HAProxy >= 3.2.0 < 3.2.26`
- `HAProxy >= 3.3.0 < 3.3.17`
- `HAProxy >= 3.4.0 < 3.4.6`
- `HAProxy >= 3.5-dev < 3.5-dev9`
- `enterprise_edition >= 3.2.0r1 < 3.2r1-378.1259`
- `enterprise_edition >= 3.3.0r1 < 3.3r1-377.1005`
- `kubernetes_ingress_controller >= 3.2.0 < 3.2.17`
- `kubernetes_ingress_controller_enterprise >= 3.2.0 < 3.2.17-ee1`
- `kubernetes_ingress_controller_enterprise >= 3.0 < 3.0.16-ee17`
- `kubernetes_ingress_controller_enterprise >= 1.11 < 1.11.14-ee11`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.