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HAProxy 3.4 vulnerabilities

2 known CVEs affect the 3.4 line of HAProxy.

9.0 max CVSS

Fixed in

3.4.1
Check your versionhaproxy -v

CVEs affecting 3.4

CVE Title CVSS Exploited EPSS Published
CVE-2026-55203 HAProxy - Integer Overflow in FCGI Demux Record Length Field 9.0 — 2026-06-19
CVE-2026-55204 HAProxy - NULL Pointer Dereference in hpack_dht_insert Function 8.7 — 2026-06-19

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Data: CVE List (CVE® Program), NVD, CISA KEV, FIRST EPSS (see EPSS at https://www.first.org/epss), endoflife.date. Software list: awesome-selfhosted (CC BY-SA 3.0).