CVE-2026-55204

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Source
https://cve.org/CVERecord?id=CVE-2026-55204
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55204.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-55204
Aliases
Downstream
ALSA (3)
AZL (1)
CGA (14)
CLSA (8)
DEBIAN (1)
MGASA (1)
MINI (7)
OESA (1)
openSUSE (2)
RHSA (11)
RLSA (3)
SUSE (7)
UBUNTU (1)
Related
ALSA (3)
openSUSE (2)
SUSE (7)
Published
2026-06-18T16:05:52Z
Modified
2026-11-04T07:22:46Z
Severity
  • 8.7 (High) CVSS_V4 - 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 CVSS Calculator
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.

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

Affected packages

Git / github.com/haproxy/haproxy

Affected ranges

Type
GIT
Repo
https://github.com/haproxy/haproxy
Events
Introduced
7832fb21fe2dd11ce44e996d8e86802731b871b2
Fixed
aed953088ebfdf6046e4a8d362f97d391c5793b4
Fixed
9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513
Database specific
Show details 
{
    "extracted_events": [
        {
            "cpe": "cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:*",
            "range": [
                {
                    "introduced": "3.3"
                },
                {
                    "fixed": "3.4.1"
                }
            ],
            "source": "CPE_RANGE"
        },
        {
            "range": [
                {
                    "fixed": "9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513"
                }
            ],
            "source": "REFERENCES_COMMIT"
        }
    ]
}

Affected versions

v3.*
v3.3.0
v3.4-dev0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55204.json"
vanir_signatures 
[
    {
        "deprecated": false,
        "digest": {
            "function_hash": "338751424987132939024747892497198054148",
            "length": 2455
        },
        "id": "CVE-2026-55204-0d78daeb",
        "signature_type": "Function",
        "signature_version": "v1",
        "source": "https://github.com/haproxy/haproxy/commit/9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513",
        "target": {
            "file": "src/hpack-tbl.c",
            "function": "hpack_dht_insert"
        }
    },
    {
        "deprecated": false,
        "digest": {
            "line_hashes": [
                "40908380705076211766954459725958104",
                "264508472132916529779782027168019563567",
                "7199169709347451960990779938033903923",
                "211161776252394108731142819930810131911"
            ],
            "threshold": 0.9
        },
        "id": "CVE-2026-55204-4609dae9",
        "signature_type": "Line",
        "signature_version": "v1",
        "source": "https://github.com/haproxy/haproxy/commit/9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513",
        "target": {
            "file": "src/hpack-tbl.c"
        }
    }
]
vanir_signatures_modified 
"2026-11-04T07:22:46Z"