What is CVE-2026-110354?

CVE-2026-110354 is a high-severity vulnerability in Haproxy, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 7.5/10. Published 2026-10-22.

How severe is CVE-2026-110354?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Haproxy

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.

Published 2026-10-22 · last modified 2026-10-22.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

CWE-835 — Loop with Unreachable Exit Condition (Infinite Loop)

References

git.haproxy.org/ (vendor-advisory)

Frequently asked questions

What is CVE-2026-110354?: CVE-2026-110354 is a high-severity vulnerability in Haproxy, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 7.5/10. Published 2026-10-22.
How severe is CVE-2026-110354?: High severity. CVSS v3 base score is 7.5 out of 10.