{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-54340",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-06-12T19:23:22.316Z",
        "datePublished": "2026-07-16T23:29:50.799Z",
        "dateUpdated": "2026-07-17T18:06:19.274Z"
    },
    "containers": {
        "cna": {
            "title": "h2o has HTTP/2 state amplification",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-400",
                            "lang": "en",
                            "description": "CWE-400: Uncontrolled Resource Consumption",
                            "type": "CWE"
                        }
                    ]
                },
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-770",
                            "lang": "en",
                            "description": "CWE-770: Allocation of Resources Without Limits or Throttling",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "HIGH",
                        "baseScore": 7.5,
                        "baseSeverity": "HIGH",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "NONE",
                        "privilegesRequired": "NONE",
                        "scope": "UNCHANGED",
                        "userInteraction": "NONE",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/h2o/h2o/security/advisories/GHSA-qcrr-wrhc-pgq9",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/h2o/h2o/security/advisories/GHSA-qcrr-wrhc-pgq9"
                },
                {
                    "name": "https://github.com/h2o/h2o/commit/9265bdd9a996ed992681055e3996baf3e09d2063",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/h2o/h2o/commit/9265bdd9a996ed992681055e3996baf3e09d2063"
                }
            ],
            "affected": [
                {
                    "vendor": "h2o",
                    "product": "h2o",
                    "versions": [
                        {
                            "version": "< 9265bdd",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-07-16T23:29:50.799Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit 9265bdd, there is an HTTP/2 state amplification issue that combines HPACK decompression amplification with Slowloris-style stream stalling. Amplified decoded header state can be retained by stalled HTTP/2 streams, and depending on the configuration, additional limits are needed to bound decoded header state and prevent attack. This issue has been fixed by commit 9265bdd."
                }
            ],
            "source": {
                "advisory": "GHSA-qcrr-wrhc-pgq9",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-07-17T15:26:10.914862Z",
                                "id": "CVE-2026-54340",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "yes"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-07-17T18:06:19.274Z"
                }
            }
        ]
    }
}