CVE-2026-110354ImportantNetworkRevised 30 Oct

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…

MSRC advisory NVD CVE.org

Assessment

Severity: Important
CVSS base score: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Impact: Not stated
EPSS · 30-day forecast: No EPSS score collected
Public detection template: No Nuclei template is listed in the current collected catalog
Exploitation detected: Unknown: not stated by MSRC
Exploitability: Not assessed
Publicly disclosed: Unknown: not stated by MSRC
Customer action: Required: follow the MSRC remediation guidance
Component: Mariner
Weakness: CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')
Issued by: mitre
Published: 25 Oct 2026 · October 2026
Last revised: 30 Oct 2026Information published.

CVSS 3.1 base metricsRed raises the risk · green lowers it

Attack vector: NetworkAV:N
Attack complexity: LowAC:L
Privileges required: NonePR:N
User interaction: NoneUI:N
Scope: UnchangedS:U
Confidentiality: NoneC:N
Integrity: NoneI:N
Availability: HighA:H

Updates that fix it

0 KBs

No KB listed

No KB update is listed in the collected MSRC record. Check the MSRC advisory for product releases and other remedies.

Affected products

Open Source Software

1 affected product

azl3 haproxy 2.9.11-8 on Azure Linux 3.0

What changed

Detection template: Unknown: detection-template evidence is incomplete or retained → No Nuclei template listed
6 Nov 2026 · 17:32:22 UTC
Detection template: No Nuclei template listed → Unknown: detection-template evidence is incomplete or retained
6 Nov 2026 · 16:31:02 UTC
Detection template: Unknown: detection-template evidence is incomplete or retained → No Nuclei template listed
2 Nov 2026 · 17:30:39 UTC
Detection template: No Nuclei template listed → Unknown: detection-template evidence is incomplete or retained
2 Nov 2026 · 16:27:39 UTC
Detection template: No Nuclei template listed · Customer action: Required: apply the update → Required: follow the MSRC remediation guidance · Public disclosure: No → Unknown: not stated by MSRC · Exploitation detected: Not reported by MSRC → Unknown: not stated by MSRC
29 Oct 2026

Page history

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Cite this version

Field-level log (23)

Up to 100 recent field edits are shown; older edits may be outside retention.

6 Nov 2026 · 17:32:22 UTC Public detection templateUnknown: detection-template evidence is incomplete or retained → No Nuclei template listed
6 Nov 2026 · 17:32:22 UTC Source coverage: public-exploit-codeIncomplete → Current
6 Nov 2026 · 17:32:22 UTC Source coverage: first-epssIncomplete → Current
6 Nov 2026 · 17:32:22 UTC Source coverage: msrc-cvrfIncomplete → Current
6 Nov 2026 · 16:31:02 UTC Public detection templateNo Nuclei template listed → Unknown: detection-template evidence is incomplete or retained
6 Nov 2026 · 16:31:02 UTC Source coverage: public-exploit-codeCurrent → Incomplete
6 Nov 2026 · 16:31:02 UTC Source coverage: first-epssCurrent → Incomplete
6 Nov 2026 · 16:31:02 UTC Source coverage: msrc-cvrfCurrent → Incomplete
2 Nov 2026 · 17:30:39 UTC Public detection templateUnknown: detection-template evidence is incomplete or retained → No Nuclei template listed
2 Nov 2026 · 17:30:39 UTC Source coverage: public-exploit-codeIncomplete → Current
2 Nov 2026 · 17:30:39 UTC Source coverage: first-epssIncomplete → Current
2 Nov 2026 · 17:30:39 UTC Source coverage: msrc-cvrfIncomplete → Current
2 Nov 2026 · 16:27:39 UTC Public detection templateNo Nuclei template listed → Unknown: detection-template evidence is incomplete or retained
2 Nov 2026 · 16:27:39 UTC Source coverage: public-exploit-codeCurrent → Incomplete
2 Nov 2026 · 16:27:39 UTC Source coverage: first-epssCurrent → Incomplete
2 Nov 2026 · 16:27:39 UTC Source coverage: msrc-cvrfCurrent → Incomplete
30 Oct 2026 · 07:19:14 UTC Last revised28 Oct 2026 14:45 UTC → 30 Oct 2026 01:45 UTC
29 Oct 2026 · 20:19:26 UTC Public detection templateNo Nuclei template listed
29 Oct 2026 · 20:19:26 UTC EPSSNot scored → No EPSS score collected
29 Oct 2026 · 20:19:26 UTC Customer actionRequired: apply the update → Required: follow the MSRC remediation guidance
29 Oct 2026 · 20:19:26 UTC Publicly disclosedNo → Unknown: not stated by MSRC
29 Oct 2026 · 20:19:26 UTC Exploitation detectedNot reported by MSRC → Unknown: not stated by MSRC
28 Oct 2026 · 19:05:35 UTC Last revised26 Oct 2026 14:49 UTC → 28 Oct 2026 14:45 UTC

Explore global source statements, affected packages and advisory history for CVE-2026-110354. The catalog has a separate collection scope from Microsoft release records.

cve-program · CVE-2026-110354

Published

HAProxy

Vendor product

Original vendor version evidence · not evaluated as a NuGet range

{
                    "defaultStatus": "unaffected",
                    "modules": [
                        "mux-h1"
                    ],
                    "product": "HAProxy",
                    "programFiles": [
                        "src/h1_htx.c"
                    ],
                    "programRoutines": [
                        {
                            "name": "h1_parse_msg_data"
                        }
                    ],
                    "repo": "https://git.haproxy.org/git/haproxy.git",
                    "vendor": "HAProxy",
                    "versions": [
                        {
                            "lessThan": "3.0.30",
                            "status": "affected",
                            "version": "3.0.0",
                            "versionType": "custom"
                        },
                        {
                            "lessThan": "3.2.26",
                            "status": "affected",
                            "version": "3.2.0",
                            "versionType": "custom"
                        },
                        {
                            "lessThan": "3.3.17",
                            "status": "affected",
                            "version": "3.3.0",
                            "versionType": "custom"
                        },
                        {
                            "lessThan": "3.4.6",
                            "status": "affected",
                            "version": "3.4.0",
                            "versionType": "custom"
                        },
                        {
                            "lessThan": "3.5-dev9",
                            "status": "affected",
                            "version": "3.5-dev",
                            "versionType": "custom"
                        }
                    ]
                }

HAProxy Enterprise Edition

Vendor product

Original vendor version evidence · not evaluated as a NuGet range

{
                    "defaultStatus": "unaffected",
                    "product": "HAProxy Enterprise Edition",
                    "vendor": "HAProxy",
                    "versions": [
                        {
                            "lessThan": "3.0r1-362.1441",
                            "status": "affected",
                            "version": "3.0r1",
                            "versionType": "custom"
                        },
                        {
                            "lessThan": "3.2r1-378.1259",
                            "status": "affected",
                            "version": "3.2r1",
                            "versionType": "custom"
                        },
                        {
                            "lessThan": "3.3r1-377.1005",
                            "status": "affected",
                            "version": "3.3r1",
                            "versionType": "custom"
                        }
                    ]
                }

HAProxy Kubernetes Ingress Controller

Vendor product

Original vendor version evidence · not evaluated as a NuGet range

{
                    "defaultStatus": "unaffected",
                    "product": "HAProxy Kubernetes Ingress Controller",
                    "vendor": "HAProxy Technologies",
                    "versions": [
                        {
                            "lessThan": "3.2.17",
                            "status": "affected",
                            "version": "3.2.0",
                            "versionType": "custom"
                        }
                    ]
                }

Kubernetes Ingress Controller Enterprise

Vendor product

Original vendor version evidence · not evaluated as a NuGet range

{
                    "defaultStatus": "unaffected",
                    "product": "Kubernetes Ingress Controller Enterprise",
                    "vendor": "HAProxy Technologies",
                    "versions": [
                        {
                            "lessThan": "3.2.17-ee1",
                            "status": "affected",
                            "version": "3.2.0",
                            "versionType": "custom"
                        },
                        {
                            "lessThan": "3.0.16-ee17",
                            "status": "affected",
                            "version": "3.0",
                            "versionType": "custom"
                        },
                        {
                            "lessThan": "1.11.14-ee11",
                            "status": "affected",
                            "version": "1.11",
                            "versionType": "custom"
                        }
                    ]
                }

Original source record · Cite this exact observation · Complete original publisher JSON