Is CVE-2026-55204 actively exploited?

No active exploitation of CVE-2026-55204 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-55204 be exploited remotely?

Yes. CVE-2026-55204 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-55204?

CVE-2026-55204 has a CVSS score of 7.5 (HIGH).

HOME VULNERABILITIESCVE-2026-55204

HIGH

CVE-2026-55204

CWE-476Published: June 18, 2026· Updated: Jun 22, 2026

7.5

CVSS v3.1

Official Description

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.

NVD Source

Technical Analysis

CVE-2026-55204 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.