CVE-2026-110354

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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.haproxy.org/?p=haproxy.git;a=commit;h=077906da140a35873bf451d7e9f67646c9f37c81

Configurations

No configuration.

History

22 Oct 2026, 03:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-22 03:16

Updated : 2026-10-22 19:17

NVD link : CVE-2026-110354

Mitre link : CVE-2026-110354

CVE.ORG link : CVE-2026-110354

JSON object : View

Products Affected

No product.

CWE

CWE-835

Loop with Unreachable Exit Condition ('Infinite Loop')

{"id": "CVE-2026-110354", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-110354", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-22T13:43:28.678756Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "cve@mitre.org", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}]}, "affected": [{"source": "cve@mitre.org", "affectedData": [{"repo": "https://git.haproxy.org/git/haproxy.git", "vendor": "HAProxy", "modules": ["mux-h1"], "product": "HAProxy", "versions": [{"status": "affected", "version": "3.0.0", "lessThan": "3.0.30", "versionType": "custom"}, {"status": "affected", "version": "3.2.0", "lessThan": "3.2.26", "versionType": "custom"}, {"status": "affected", "version": "3.3.0", "lessThan": "3.3.17", "versionType": "custom"}, {"status": "affected", "version": "3.4.0", "lessThan": "3.4.6", "versionType": "custom"}, {"status": "affected", "version": "3.5-dev", "lessThan": "3.5-dev9", "versionType": "custom"}], "programFiles": ["src/h1_htx.c"], "defaultStatus": "unaffected", "programRoutines": [{"name": "h1_parse_msg_data"}]}, {"vendor": "HAProxy", "product": "HAProxy Enterprise Edition", "versions": [{"status": "affected", "version": "3.0r1", "lessThan": "3.0r1-362.1441", "versionType": "custom"}, {"status": "affected", "version": "3.2r1", "lessThan": "3.2r1-378.1259", "versionType": "custom"}, {"status": "affected", "version": "3.3r1", "lessThan": "3.3r1-377.1005", "versionType": "custom"}], "defaultStatus": "unaffected"}, {"vendor": "HAProxy Technologies", "product": "HAProxy Kubernetes Ingress Controller", "versions": [{"status": "affected", "version": "3.2.0", "lessThan": "3.2.17", "versionType": "custom"}], "defaultStatus": "unaffected"}, {"vendor": "HAProxy Technologies", "product": "Kubernetes Ingress Controller Enterprise", "versions": [{"status": "affected", "version": "3.2.0", "lessThan": "3.2.17-ee1", "versionType": "custom"}, {"status": "affected", "version": "3.0", "lessThan": "3.0.16-ee17", "versionType": "custom"}, {"status": "affected", "version": "1.11", "lessThan": "1.11.14-ee11", "versionType": "custom"}], "defaultStatus": "unaffected"}]}], "published": "2026-10-22T03:16:31.427", "references": [{"url": "https://git.haproxy.org/?p=haproxy.git;a=commit;h=077906da140a35873bf451d7e9f67646c9f37c81", "source": "cve@mitre.org"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "cve@mitre.org", "description": [{"lang": "en", "value": "CWE-835"}]}], "descriptions": [{"lang": "en", "value": "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."}], "lastModified": "2026-10-22T19:17:35.660", "sourceIdentifier": "cve@mitre.org"}