{"id":"BIT-haproxy-2026-55204","summary":"HAProxy - NULL Pointer Dereference in hpack_dht_insert Function","details":"HAProxy through  3.4.0, fixed in commit 9a6d1fe, contains a null pointer dereference vulnerability in hpack_dht_insert() within src/hpack-tbl.c that fails to validate the return value of hpack_dht_defrag() when the memory pool is exhausted. An attacker can trigger HPACK dynamic table insertions under memory pressure to dereference a NULL pointer and crash HAProxy worker processes, causing denial of service.","aliases":["CVE-2026-55204"],"modified":"2026-06-29T08:15:09.376690152Z","published":"2026-06-29T05:40:50.508Z","database_specific":{"severity":"High","cpes":["cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:*"]},"references":[{"type":"WEB","url":"https://github.com/haproxy/haproxy/commit/9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55204"},{"type":"WEB","url":"https://www.vulncheck.com/advisories/haproxy-null-pointer-dereference-in-hpack-dht-insert-function"}],"affected":[{"package":{"name":"haproxy","ecosystem":"Bitnami","purl":"pkg:bitnami/haproxy"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.4.1"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/haproxy/BIT-haproxy-2026-55204.json"},"severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"}]}],"schema_version":"1.7.5"}