{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-18503",
        "assignerOrgId": "28c92f92-d60d-412d-b760-e73465c3df22",
        "state": "PUBLISHED",
        "assignerShortName": "PSF",
        "dateReserved": "2026-07-31T16:35:42.902Z",
        "datePublished": "2026-08-10T13:45:31.618Z",
        "dateUpdated": "2026-08-13T00:28:22.443Z"
    },
    "containers": {
        "cna": {
            "affected": [
                {
                    "defaultStatus": "unaffected",
                    "modules": [
                        "csv"
                    ],
                    "product": "CPython",
                    "repo": "https://github.com/python/cpython",
                    "vendor": "Python Software Foundation",
                    "versions": [
                        {
                            "version": "0",
                            "lessThan": "3.10.21",
                            "status": "affected",
                            "versionType": "python"
                        },
                        {
                            "version": "3.11.0",
                            "lessThan": "3.11.16",
                            "status": "affected",
                            "versionType": "python"
                        },
                        {
                            "version": "3.12.0",
                            "lessThan": "3.12.14",
                            "status": "affected",
                            "versionType": "python"
                        },
                        {
                            "version": "3.13.0",
                            "lessThan": "3.13.15",
                            "status": "affected",
                            "versionType": "python"
                        },
                        {
                            "version": "3.14.0",
                            "lessThan": "3.14.7",
                            "status": "affected",
                            "versionType": "python"
                        },
                        {
                            "version": "3.15.0a1",
                            "lessThan": "3.15.0rc1",
                            "status": "affected",
                            "versionType": "python"
                        }
                    ]
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "type": "remediation developer",
                    "value": "Serhiy Storchaka (https://github.com/serhiy-storchaka)"
                },
                {
                    "lang": "en",
                    "type": "reporter",
                    "value": "Jack Desert (https://github.com/jackdesert)"
                },
                {
                    "lang": "en",
                    "type": "reporter",
                    "value": "Sean Gilligan (https://github.com/sg3-141-592)"
                },
                {
                    "lang": "en",
                    "type": "coordinator",
                    "value": "Seth Larson (https://github.com/sethmlarson)"
                }
            ],
            "descriptions": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "type": "text/html",
                            "value": "Attacker-controlled CSV samples can trigger super-linear \nregular-expression work during dialect sniffing and consume significant \nCPU when applications pass unbounded input to csv.Sniffer.sniff()."
                        }
                    ],
                    "value": "Attacker-controlled CSV samples can trigger super-linear \nregular-expression work during dialect sniffing and consume significant \nCPU when applications pass unbounded input to csv.Sniffer.sniff()."
                }
            ],
            "metrics": [
                {
                    "cvssV4_0": {
                        "Automatable": "NOT_DEFINED",
                        "Recovery": "NOT_DEFINED",
                        "Safety": "NOT_DEFINED",
                        "attackComplexity": "LOW",
                        "attackRequirements": "NONE",
                        "attackVector": "LOCAL",
                        "baseScore": 2.4,
                        "baseSeverity": "LOW",
                        "exploitMaturity": "NOT_DEFINED",
                        "privilegesRequired": "LOW",
                        "providerUrgency": "NOT_DEFINED",
                        "subAvailabilityImpact": "NONE",
                        "subConfidentialityImpact": "NONE",
                        "subIntegrityImpact": "NONE",
                        "userInteraction": "PASSIVE",
                        "valueDensity": "NOT_DEFINED",
                        "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
                        "version": "4.0",
                        "vulnAvailabilityImpact": "LOW",
                        "vulnConfidentialityImpact": "NONE",
                        "vulnIntegrityImpact": "NONE",
                        "vulnerabilityResponseEffort": "NOT_DEFINED"
                    },
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ]
                }
            ],
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-1176",
                            "description": "CWE-1176",
                            "lang": "en",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "28c92f92-d60d-412d-b760-e73465c3df22",
                "shortName": "PSF",
                "dateUpdated": "2026-08-13T00:28:22.443Z"
            },
            "references": [
                {
                    "tags": [
                        "vendor-advisory"
                    ],
                    "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/KQ7NBMCPAZJHRROQXJQE4GMXGLD5KHBS/"
                },
                {
                    "tags": [
                        "patch"
                    ],
                    "url": "https://github.com/python/cpython/pull/153694"
                },
                {
                    "tags": [
                        "issue-tracking"
                    ],
                    "url": "https://github.com/python/cpython/issues/98820"
                },
                {
                    "tags": [
                        "patch"
                    ],
                    "url": "https://github.com/python/cpython/commit/063d4555c94ef412c731527dbf30193327f2ee82"
                },
                {
                    "tags": [
                        "patch"
                    ],
                    "url": "https://github.com/python/cpython/commit/476fb09cdb0d73e645849d98c610e7e5697ce7c9"
                },
                {
                    "tags": [
                        "patch"
                    ],
                    "url": "https://github.com/python/cpython/commit/89f29c760c02774b099ddd6863268eb13fa3946a"
                },
                {
                    "tags": [
                        "patch"
                    ],
                    "url": "https://github.com/python/cpython/commit/b30c7fa9edd921a118f286e9f90f560777fa693b"
                },
                {
                    "tags": [
                        "patch"
                    ],
                    "url": "https://github.com/python/cpython/commit/b09a67a20c464f8288c9f9a6b9c7082a74560024"
                },
                {
                    "tags": [
                        "patch"
                    ],
                    "url": "https://github.com/python/cpython/commit/fd78b565d7c326f96ae903ab945b47f35d829cf4"
                }
            ],
            "source": {
                "discovery": "UNKNOWN"
            },
            "title": "Super-linear CPU usage for unbounded input to csv.Sniffer.sniff()",
            "x_generator": {
                "engine": "cvelib 1.8.0"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-08-10T17:56:17.853221Z",
                                "id": "CVE-2026-18503",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "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": "2026-08-10T17:56:28.336Z"
                }
            }
        ]
    }
}