{"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"}}]}}