{"id":"CVE-2026-18503","revision":null,"records":[{"revision":"74c69f03e9754a679dcf79417a2cf9ce","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-18503","aliases":[],"title":"Super-linear CPU usage for unbounded input to csv.Sniffer.sniff()","description":"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().","state":0,"publishedAt":"2026-08-10T13:45:31.618+00:00","modifiedAt":"2026-10-14T00:34:46.583+00:00","affected":[{"ecosystem":"Vendor product","name":"CPython","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"defaultStatus\": \"unaffected\",\n                    \"modules\": [\n                        \"csv\"\n                    ],\n                    \"product\": \"CPython\",\n                    \"repo\": \"https://github.com/python/cpython\",\n                    \"vendor\": \"Python Software Foundation\",\n                    \"versions\": [\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"3.10.21\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"python\"\n                        },\n                        {\n                            \"version\": \"3.11.0\",\n                            \"lessThan\": \"3.11.16\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"python\"\n                        },\n                        {\n                            \"version\": \"3.12.0\",\n                            \"lessThan\": \"3.12.14\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"python\"\n                        },\n                        {\n                            \"version\": \"3.13.0\",\n                            \"lessThan\": \"3.13.15\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"python\"\n                        },\n                        {\n                            \"version\": \"3.14.0\",\n                            \"lessThan\": \"3.14.7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"python\"\n                        },\n                        {\n                            \"version\": \"3.15.0a1\",\n                            \"lessThan\": \"3.15.0rc1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"python\"\n                        },\n                        {\n                            \"version\": \"3.16.0a1\",\n                            \"lessThan\": \"3.16.0\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"python\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"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","score":2.4,"severity":"LOW"}],"references":["https://mail.python.org/archives/list/security-announce@python.org/thread/KQ7NBMCPAZJHRROQXJQE4GMXGLD5KHBS/","https://github.com/python/cpython/pull/153694","https://github.com/python/cpython/issues/98820","https://github.com/python/cpython/commit/063d4555c94ef412c731527dbf30193327f2ee82","https://github.com/python/cpython/commit/476fb09cdb0d73e645849d98c610e7e5697ce7c9","https://github.com/python/cpython/commit/89f29c760c02774b099ddd6863268eb13fa3946a","https://github.com/python/cpython/commit/b30c7fa9edd921a118f286e9f90f560777fa693b","https://github.com/python/cpython/commit/b09a67a20c464f8288c9f9a6b9c7082a74560024","https://github.com/python/cpython/commit/fd78b565d7c326f96ae903ab945b47f35d829cf4"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-18503","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-18503","identifiers":["CVE-2026-18503"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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