CVE-2026-72818

{"id": "CVE-2026-72818", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-72818", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-21T11:05:49.886911Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 8.7, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "disclosure@vulncheck.com", "affectedData": [{"repo": "https://github.com/nltk/nltk", "vendor": "nltk", "product": "nltk", "versions": [{"status": "affected", "version": "0", "lessThan": "3.10.1", "versionType": "semver"}, {"status": "unaffected", "version": "3.10.1", "versionType": "semver"}], "packageURL": "pkg:pypi/nltk", "packageName": "nltk", "programFiles": ["nltk/tokenize/casual.py"], "collectionURL": "https://pypi.org", "defaultStatus": "unaffected"}]}], "published": "2026-08-20T22:18:05.087", "references": [{"url": "https://github.com/nltk/nltk", "source": "disclosure@vulncheck.com"}, {"url": "https://github.com/nltk/nltk/blob/3.9.4/nltk/tokenize/casual.py", "source": "disclosure@vulncheck.com"}, {"url": "https://github.com/nltk/nltk/issues/3704", "source": "disclosure@vulncheck.com"}, {"url": "https://github.com/nltk/nltk/releases/tag/v3.10.1", "source": "disclosure@vulncheck.com"}, {"url": "https://www.vulncheck.com/advisories/nltk-tweettokenizer-url-pattern-backtracks-catastrophically-on-naked-domain-like-input", "source": "disclosure@vulncheck.com"}, {"url": "https://github.com/nltk/nltk/issues/3704", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "description": [{"lang": "en", "value": "CWE-1333"}]}], "descriptions": [{"lang": "en", "value": "The URLS regular expression in nltk/tokenize/casual.py, compiled into TweetTokenizer.WORD_RE and applied by TweetTokenizer.tokenize, contains a naked-domain branch whose domain-label prefix [a-z0-9]+(?:[.\\-][a-z0-9]+)* is unbounded. Input consisting of many alternating label separators can be partitioned in exponentially many ways, and because the branch also requires a trailing top-level domain that such input never supplies, the engine explores those partitions before failing at each offset. A few kilobytes of input therefore consumes seconds to minutes of single-threaded CPU, and the HANG_RE substitution performed before matching does not collapse the pattern. TweetTokenizer is intended for tokenizing untrusted social-media text, so any service that applies it, or the module-level casual_tokenize, to submitted text can be stalled per request without authentication. Version 3.10.1 bounds the label repetition."}, {"lang": "es", "value": "La expresi\u00f3n regular URLS en nltk/tokenize/casual.py, compilada en TweetTokenizer.WORD_RE y aplicada por TweetTokenizer.tokenize, contiene una rama de dominio \u2019desnudo\u2019 cuyo prefijo de etiqueta de dominio [a-z0-9]+(?:[.\\-][a-z0-9]+)* es ilimitado. La entrada que consiste en muchos separadores de etiquetas alternos puede ser particionada de exponencialmente muchas maneras, y debido a que la rama tambi\u00e9n requiere un dominio de nivel superior final que dicha entrada nunca proporciona, el motor explora esas particiones antes de fallar en cada desplazamiento. Unos pocos kilobytes de entrada, por lo tanto, consume de segundos a minutos de CPU de un solo hilo, y la sustituci\u00f3n HANG_RE realizada antes de la coincidencia no colapsa el patr\u00f3n. TweetTokenizer est\u00e1 dise\u00f1ado para tokenizar texto no confiable de redes sociales, por lo que cualquier servicio que lo aplique, o el casual_tokenize a nivel de m\u00f3dulo, a texto enviado puede ser paralizado por solicitud sin autenticaci\u00f3n. La versi\u00f3n 3.10.1 limita la repetici\u00f3n de etiquetas."}], "lastModified": "2026-10-26T10:10:00.140", "sourceIdentifier": "disclosure@vulncheck.com"}