{"id":"CVE-2026-81723","title":"NLTK versions before 3.10.3 contain a quadratic CPU exhaustion vulnerability in XMLCorpusView._read_xml_fragment() that rescans accumulated XML fragments on every 1 KiB block read","summary":"NLTK versions before 3.10.3 contain a quadratic CPU exhaustion vulnerability in XMLCorpusView._read_xml_fragment() that rescans accumulated XML fragments on every 1 KiB block read. Attackers can provide malformed XML corpus files to caus…","severity":"low","cvss":3.7,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L","cwe":["CWE-400","CWE-407","CWE-776"],"vendor":"nltk","product":"nltk","affected":["nltk < 3.10.3"],"patched":["nltk 3.10.3"],"published":"2026-08-27","updated":"2026-09-24","sourceUpdated":"2026-09-24T20:44:42.207","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-81723","references":[{"url":"https://github.com/nltk/nltk/security/advisories/GHSA-vp2x-qp44-57v7","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/nltk-before-3.10.3-quadratic-cpu-exhaustion-via-xmlcorpusview","label":"disclosure@vulncheck.com"},{"url":"https://github.com/nltk/nltk/security/advisories/GHSA-vp2x-qp44-57v7","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-81723"},{"url":"https://github.com/nltk/nltk/commit/7808692d451b962711005d954859bb83aabcf8fa"},{"url":"https://github.com/nltk/nltk"},{"url":"https://github.com/nltk/nltk/releases/tag/v3.10.3"},{"url":"https://pypi.org/project/nltk"},{"url":"https://github.com/advisories/GHSA-vp2x-qp44-57v7"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81723.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-81723"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2525090"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-81723"}],"tags":["nvd","osv","pip","ghsa","csaf","vex","red-hat","score-dispute"],"epss":0.00281,"epssPercentile":0.20432,"aliases":["GHSA-vp2x-qp44-57v7","PYSEC-2026-3871"],"ecosystem":"pip","ingestedAt":"2026-09-02T14:45:30.348Z","scores":{"nvd":3.7,"vendor":5.9},"slug":"CVE-2026-81723","body":"## Overview\n\nNLTK versions before 3.10.3 contain a quadratic CPU exhaustion vulnerability in XMLCorpusView._read_xml_fragment() that rescans accumulated XML fragments on every 1 KiB block read. Attackers can provide malformed XML corpus files to cause severe CPU consumption and denial of service through affected readers like BNCCorpusReader.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-81723)\n\nAffected packages:\n\n- `nltk < 3.10.3`\n\nPatched in:\n\n- `nltk 3.10.3`\n\nSource: https://osv.dev/vulnerability/GHSA-vp2x-qp44-57v7\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Exploit Intelligence, Lightspeed Core, OpenShift Lightspeed, Red Hat Ansible Automation Platform 2, Red Hat OpenShift AI (RHOAI) · no fix planned: Exploit Intelligence, Red Hat Ansible Automation Platform 2, Lightspeed Core, OpenShift Lightspeed, … · updated 2026-10-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81723.json)","depth":"sunlit","depthScore":20,"depthScoreParts":{"impact":20.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":202003,"id":"CVE-2026-81723","ts":1789400002159,"field":"severity","old":"medium","new":"low"},{"seq":200730,"id":"CVE-2026-81723","ts":1789397588102,"field":"severity","old":"low","new":"medium"},{"seq":199425,"id":"CVE-2026-81723","ts":1789395501914,"field":"severity","old":"medium","new":"low"},{"seq":198670,"id":"CVE-2026-81723","ts":1789392190507,"field":"severity","old":"low","new":"medium"},{"seq":197001,"id":"CVE-2026-81723","ts":1789384277255,"field":"severity","old":"medium","new":"low"},{"seq":196361,"id":"CVE-2026-81723","ts":1789383751666,"field":"severity","old":"low","new":"medium"},{"seq":195289,"id":"CVE-2026-81723","ts":1789380558912,"field":"severity","old":"medium","new":"low"},{"seq":194132,"id":"CVE-2026-81723","ts":1789378730872,"field":"severity","old":"low","new":"medium"},{"seq":192919,"id":"CVE-2026-81723","ts":1789376499797,"field":"severity","old":"medium","new":"low"},{"seq":191706,"id":"CVE-2026-81723","ts":1789373593133,"field":"severity","old":"low","new":"medium"},{"seq":190491,"id":"CVE-2026-81723","ts":1789369456514,"field":"severity","old":"medium","new":"low"},{"seq":189278,"id":"CVE-2026-81723","ts":1789368375713,"field":"severity","old":"low","new":"medium"},{"seq":188061,"id":"CVE-2026-81723","ts":1789365222622,"field":"severity","old":"medium","new":"low"},{"seq":186848,"id":"CVE-2026-81723","ts":1789363457143,"field":"severity","old":"low","new":"medium"},{"seq":185634,"id":"CVE-2026-81723","ts":1789361210084,"field":"severity","old":"medium","new":"low"},{"seq":184421,"id":"CVE-2026-81723","ts":1789358321212,"field":"severity","old":"low","new":"medium"},{"seq":182672,"id":"CVE-2026-81723","ts":1789354307922,"field":"severity","old":"medium","new":"low"},{"seq":181465,"id":"CVE-2026-81723","ts":1789353287032,"field":"severity","old":"low","new":"medium"},{"seq":180258,"id":"CVE-2026-81723","ts":1789350270364,"field":"severity","old":"medium","new":"low"},{"seq":179051,"id":"CVE-2026-81723","ts":1789348259328,"field":"severity","old":"low","new":"medium"},{"seq":177844,"id":"CVE-2026-81723","ts":1789346360668,"field":"severity","old":"medium","new":"low"},{"seq":176637,"id":"CVE-2026-81723","ts":1789343159552,"field":"severity","old":"low","new":"medium"},{"seq":174754,"id":"CVE-2026-81723","ts":1789334857640,"field":"severity","old":"medium","new":"low"},{"seq":173549,"id":"CVE-2026-81723","ts":1789333670476,"field":"severity","old":"low","new":"medium"},{"seq":172363,"id":"CVE-2026-81723","ts":1789331084683,"field":"severity","old":"medium","new":"low"},{"seq":171177,"id":"CVE-2026-81723","ts":1789328753076,"field":"severity","old":"low","new":"medium"},{"seq":169972,"id":"CVE-2026-81723","ts":1789327153490,"field":"severity","old":"medium","new":"low"},{"seq":168767,"id":"CVE-2026-81723","ts":1789323810038,"field":"severity","old":"low","new":"medium"},{"seq":167562,"id":"CVE-2026-81723","ts":1789319675097,"field":"severity","old":"medium","new":"low"},{"seq":166357,"id":"CVE-2026-81723","ts":1789318740841,"field":"severity","old":"low","new":"medium"},{"seq":165152,"id":"CVE-2026-81723","ts":1789315779309,"field":"severity","old":"medium","new":"low"},{"seq":163947,"id":"CVE-2026-81723","ts":1789313605443,"field":"severity","old":"low","new":"medium"},{"seq":162742,"id":"CVE-2026-81723","ts":1789311892008,"field":"severity","old":"medium","new":"low"},{"seq":161537,"id":"CVE-2026-81723","ts":1789308700793,"field":"severity","old":"low","new":"medium"},{"seq":159650,"id":"CVE-2026-81723","ts":1789300460292,"field":"severity","old":"medium","new":"low"},{"seq":156639,"id":"CVE-2026-81723","ts":1789294730674,"field":"severity","old":"low","new":"medium"},{"seq":155434,"id":"CVE-2026-81723","ts":1789292954428,"field":"severity","old":"medium","new":"low"},{"seq":154229,"id":"CVE-2026-81723","ts":1789289770678,"field":"severity","old":"low","new":"medium"},{"seq":153096,"id":"CVE-2026-81723","ts":1789285309872,"field":"severity","old":"medium","new":"low"},{"seq":152519,"id":"CVE-2026-81723","ts":1789281255302,"field":"severity","old":"low","new":"medium"},{"seq":151480,"id":"CVE-2026-81723","ts":1789277615125,"field":"severity","old":"medium","new":"low"},{"seq":150441,"id":"CVE-2026-81723","ts":1789276229839,"field":"severity","old":"low","new":"medium"},{"seq":149408,"id":"CVE-2026-81723","ts":1789273813500,"field":"severity","old":"medium","new":"low"},{"seq":148375,"id":"CVE-2026-81723","ts":1789271312107,"field":"severity","old":"low","new":"medium"},{"seq":146407,"id":"CVE-2026-81723","ts":1789269375561,"field":"severity","old":"medium","new":"low"},{"seq":145212,"id":"CVE-2026-81723","ts":1789266325234,"field":"severity","old":"low","new":"medium"},{"seq":144116,"id":"CVE-2026-81723","ts":1789262596318,"field":"severity","old":"medium","new":"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