CVE-2026-55204CWE-476

CVE-2026-55204

High · published June 18, 2026

CVSS v3.1
7.5
EPSS
0%
Percentile
40.7
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00484 · 40.7th percentile
Weakness
CWE-476 · NULL Pointer Dereference
Published
2026-06-18T21:16Z
Affected products (6)
ProductVersionsFixed in
haproxy/haproxy< 2.4.362.4.36
haproxy/haproxy≥ 2.5, < 2.6.302.6.30
haproxy/haproxy≥ 2.7, < 2.8.252.8.25
haproxy/haproxy≥ 2.9, < 3.0.243.0.24
haproxy/haproxy≥ 3.1, < 3.2.203.2.20
haproxy/haproxy≥ 3.3, < 3.4.13.4.1
References (2)
https://github.com/haproxy/haproxy/commit/9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513 · [email protected]https://www.vulncheck.com/advisories/haproxy-null-pointer-dereference-in-hpack-dht-insert-function · [email protected]
EPSS history
Timeline
  • 18 JUN 16:05Z
    HAProxy - NULL Pointer Dereference in hpack_dht_insert Function
    cvelistv5