{"id":"CVE-2026-18503","title":"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().","summary":"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().","severity":"low","cwe":["CWE-1176"],"published":"2026-08-10","updated":"2026-10-14","sourceUpdated":"2026-10-14T01:17:06.473","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-18503","references":[{"url":"https://github.com/python/cpython/commit/063d4555c94ef412c731527dbf30193327f2ee82","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/476fb09cdb0d73e645849d98c610e7e5697ce7c9","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/89f29c760c02774b099ddd6863268eb13fa3946a","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/b09a67a20c464f8288c9f9a6b9c7082a74560024","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/b30c7fa9edd921a118f286e9f90f560777fa693b","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/fd78b565d7c326f96ae903ab945b47f35d829cf4","label":"cna@python.org"},{"url":"https://github.com/python/cpython/issues/98820","label":"cna@python.org"},{"url":"https://github.com/python/cpython/pull/153694","label":"cna@python.org"},{"url":"https://mail.python.org/archives/list/security-announce@python.org/thread/KQ7NBMCPAZJHRROQXJQE4GMXGLD5KHBS/","label":"cna@python.org"}],"tags":["nvd","cve.org"],"epss":0.00119,"epssPercentile":0.0177,"ingestedAt":"2026-10-14T02:10:14.762Z","vendor":"Python Software Foundation","product":"CPython","affected":["CPython < 3.10.21","CPython >= 3.11.0 < 3.11.16","CPython >= 3.12.0 < 3.12.14","CPython >= 3.13.0 < 3.13.15","CPython >= 3.14.0 < 3.14.7","CPython >= 3.15.0a1 < 3.15.0rc1","CPython >= 3.16.0a1 < 3.16.0"],"cvss":2.4,"cvssVector":"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","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-08-10T17:56:17.853221Z"},"cvssSource":"cna","slug":"CVE-2026-18503","body":"## Overview\n\nAttacker-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().\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":13,"depthScoreParts":{"impact":13.2,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":221176,"id":"CVE-2026-18503","ts":1792030796257,"field":"cvss","old":null,"new":"2.4"},{"seq":221175,"id":"CVE-2026-18503","ts":1792030796257,"field":"severity","old":"none","new":"low"}]}