{"affected":[{"defaultStatus":"unaffected","ecosystem":"pypi","packageName":"nltk","product":"nltk","source":"CNA: VulnCheck","vendor":"nltk","versions":[{"lessThan":"3.10.4","status":"affected","version":"3.2.5","versionType":"semver"},{"status":"unaffected","version":"3.10.4","versionType":"semver"}]}],"cveId":"CVE-2026-126300","cwes":["CWE-407"],"description":"NLTK from 3.2.5 before 3.10.4 contains an algorithmic complexity vulnerability in TreebankWordTokenizer.span_tokenize that allows remote attackers to cause quadratic CPU consumption through repeated list.pop(0) calls. Attackers can submit long runs of double-quote characters to services span-tokenizing untrusted text, exhausting a CPU core and degrading availability.","epss":null,"exploits":[],"kev":null,"metrics":[{"score":6.9,"severity":"medium","source":"CNA: VulnCheck","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","version":"4.0"},{"score":5.3,"severity":"medium","source":"CNA: VulnCheck","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","version":"3.1"},{"score":6.9,"severity":"medium","source":"NVD: disclosure@vulncheck.com","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","version":"4.0"},{"score":5.3,"severity":"medium","source":"NVD: disclosure@vulncheck.com","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","version":"3.1"}],"modifiedAt":1794565055043,"publishedAt":1794562585918,"references":[{"source":"CNA: VulnCheck","tags":["vendor-advisory"],"url":"https://github.com/nltk/nltk/security/advisories/GHSA-ffr9-mgrr-wcvr"},{"source":"CNA: VulnCheck","tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/nltk-from-3.2.5-before-3.10.4-cpu-exhaustion-via-treebankwordtokenizer-span-tokenize"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://github.com/nltk/nltk/security/advisories/GHSA-ffr9-mgrr-wcvr"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://www.vulncheck.com/advisories/nltk-from-3.2.5-before-3.10.4-cpu-exhaustion-via-treebankwordtokenizer-span-tokenize"}],"remediation":[],"revision":"ec9d39c65e5b9b57686bc1293eed62ce5d48a4dee11806b07933c07a9349c0d9","sources":[{"modifiedAt":1794562585918,"name":"CNA: VulnCheck","retrievedAt":1794564584398,"url":"https://www.cve.org/CVERecord?id=CVE-2026-126300"},{"modifiedAt":1794565055043,"name":"NVD","retrievedAt":1794572185918,"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-126300"}],"ssvc":null,"status":"published","title":"NLTK from 3.2.5 before 3.10.4 CPU Exhaustion via TreebankWordTokenizer.span_tokenize","updatedAt":1794572185918}