Vulnerability Details CVE-2026-55204
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.004
EPSS Ranking 30.2%
CVSS Severity
CVSS v3 Score 7.5