{"id":"CVE-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":["BIT-haproxy-2026-55204"],"modified":"2026-07-16T03:48:42.511985256Z","published":"2026-06-18T16:05:52.058Z","related":["CGA-28jh-ww24-vmmh","SUSE-SU-2026:22515-1","SUSE-SU-2026:22544-1","SUSE-SU-2026:22557-1","SUSE-SU-2026:22587-1","SUSE-SU-2026:2651-1","SUSE-SU-2026:2652-1","openSUSE-SU-2026:11090-1","openSUSE-SU-2026:21245-1"],"database_specific":{"cna_assigner":"VulnCheck","cwe_ids":["CWE-476"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55204.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55204.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55204"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/haproxy-null-pointer-dereference-in-hpack-dht-insert-function"},{"type":"FIX","url":"https://github.com/haproxy/haproxy/commit/9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513"},{"type":"PACKAGE","url":"https://github.com/haproxy/haproxy"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/haproxy/haproxy","events":[{"introduced":"0"},{"fixed":"9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"last_affected":"3.4.0"}],"source":["CPE_RANGE","REFERENCES"],"cpe":"cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:*"}}],"versions":["v3.5-dev0","v3.4.0","v3.4-dev14","v3.4-dev13","v3.4-dev12","v3.4-dev11","v3.4-dev10","v3.4-dev9","v3.4-dev8","v3.4-dev7","v3.4-dev6","v3.4-dev5","v3.4-dev4","v3.4-dev3","v3.4-dev2","v3.4-dev1","v3.4-dev0","v3.3.0","v3.3-dev14","v3.3-dev13","v3.3-dev12","v3.3-dev11","v3.3-dev10","v3.3-dev9","v3.3-dev8","v3.3-dev7","v3.3-dev6","v3.3-dev5","v3.3-dev4","v3.3-dev3","v3.3-dev2","v3.3-dev1","v3.3-dev0","v3.2.0","v3.2-dev17","v3.2-dev16","v3.2-dev15","v3.2-dev14","v3.2-dev13","v3.2-dev12","v3.2-dev11","v3.2-dev10","v3.2-dev9","v3.2-dev8","v3.2-dev7","v3.2-dev6","v3.2-dev5","v3.2-dev4","v3.2-dev3","v3.2-dev2","v3.2-dev1","v3.2-dev0","v3.1.0","v3.1-dev14","v3.1-dev13","v3.1-dev12","v3.1-dev11","v3.1-dev10","v3.1-dev9","v3.1-dev8","v3.1-dev7","v3.1-dev6","v3.1-dev5","v3.1-dev4","v3.1-dev3","v3.1-dev2","v3.1-dev1","v3.1-dev0","v3.0.0","v3.0-dev13","v3.0-dev12","v3.0-dev11","v3.0-dev10","v3.0-dev9","v3.0-dev8","v3.0-dev7","v3.0-dev6","v3.0-dev5","v3.0-dev4","v3.0-dev3","v3.0-dev2","v3.0-dev1","v3.0-dev0","v2.9.0","v2.9-dev12","v2.9-dev11","v2.9-dev10","v2.9-dev9","v2.9-dev8","v2.9-dev7","v2.9-dev6","v2.9-dev5","v2.9-dev4","v2.9-dev3","v2.9-dev2","v2.9-dev1","v2.9-dev0","v2.8.0","v2.8-dev13","v2.8-dev12","v2.8-dev11","v2.8-dev10","v2.8-dev9","v2.8-dev8","v2.8-dev7","v2.8-dev6","v2.8-dev5","v2.8-dev4","v2.8-dev3","v2.8-dev2","v2.8-dev1","v2.8-dev0","v2.7.0","v2.7-dev10","v2.7-dev9","v2.7-dev8","v2.7-dev7","v2.7-dev6","v2.7-dev5","v2.7-dev4","v2.7-dev3","v2.7-dev2","v2.7-dev1","v2.7-dev0","v2.6.0","v2.6-dev12","v2.6-dev11","v2.6-dev10","v2.6-dev9","v2.6-dev8","v2.6-dev7","v2.6-dev6","v2.6-dev5","v2.6-dev4","v2.6-dev3","v2.6-dev2","v2.6-dev1","v2.6-dev0","v2.5.0","v2.5-dev15","v2.5-dev14","v2.5-dev13","v2.5-dev12","v2.5-dev11","v2.5-dev10","v2.5-dev9","v2.5-dev8","v2.5-dev7","v2.5-dev6","v2.5-dev5","v2.5-dev4","v2.5-dev3","v2.5-dev2","v2.5-dev1","v2.5-dev0","v2.4.0","v2.4-dev19","v2.4-dev18","v2.4-dev17","v2.4-dev16","v2.4-dev15","v2.4-dev14","v2.4-dev13","v2.4-dev12","v2.4-dev11","v2.4-dev10","v2.4-dev9","v2.4-dev8","v2.4-dev7","v2.4-dev6","v2.4-dev5","v2.4-dev4","v2.4-dev3","v2.4-dev2","v2.4-dev1","v2.4-dev0","v2.3.0","v2.3-dev9","v2.3-dev8","v2.3-dev7","v2.3-dev6","v2.3-dev5","v2.3-dev4","v2.3-dev3","v2.3-dev2","v2.3-dev1","v2.3-dev0","v2.2.0","v2.2-dev12","v2.2-dev11","v2.2-dev10","v2.2-dev9","v2.2-dev8","v2.2-dev7","v2.2-dev6","v2.2-dev5","v2.2-dev4","v2.2-dev3","v2.2-dev2","v2.2-dev1","v2.2-dev0","v2.1.0","v2.1-dev5","v2.1-dev4","v2.1-dev3","v2.1-dev2","v2.1-dev1","v2.1-dev0","v2.0.0","v2.0-dev7","v2.0-dev6","v2.0-dev5","v2.0-dev4","v2.0-dev3","v2.0-dev2","v2.0-dev1","v2.0-dev0","v1.9.0","v1.9-dev11","v1.9-dev10","v1.9-dev9","v1.9-dev8","v1.9-dev7","v1.9-dev6","v1.9-dev5","v1.9-dev4","v1.9-dev3","v1.9-dev2","v1.9-dev1","v1.9-dev0","v1.8.0","v1.8-rc4","v1.8-rc3","v1.8-rc2","v1.8-rc1","v1.8-dev3","v1.8-dev2","v1.8-dev1","v1.8-dev0","v1.7.0","v1.7-dev6","v1.7-dev5","v1.7-dev4","v1.7-dev3","v1.7-dev2","v1.7-dev1","v1.7-dev0","v1.6.0","v1.6-dev7","v1.6-dev6","v1.6-dev5","v1.6-dev4","v1.6-dev3","v1.6-dev2","v1.6-dev1","v1.6-dev0","v1.5.0","v1.5-dev26","v1.5-dev25","v1.5-dev24","v1.5-dev23","v1.5-dev22","v1.5-dev21","v1.5-dev20","v1.5-dev19","v1.5-dev18","v1.5-dev17","v1.5-dev16","v1.5-dev15","v1.5-dev14","v1.5-dev13","v1.5-dev12","v1.5-dev10","v1.5-dev9","v1.5-dev8","v1.4.6","v1.4.5","v1.4.4","v1.4.3","v1.4.2","v1.4.1","v1.4.0","v1.4-rc1","v1.4-dev8","v1.4-dev7","v1.4-dev6","v1.4-dev5","v1.4-dev4","v1.4-dev3","v1.4-dev2","v1.4-dev1","v1.4-dev0","v1.3.18","v1.3.17","v1.3.16","v1.3.16-rc2","v1.3.16-rc1","v1.3.15","v1.3.14","v1.3.13","v1.3.12","v1.3.11.4","v1.3.11.3",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