{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-78683", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-08-25T01:17:12.263Z", "datePublished": "2026-08-25T01:30:39.451Z", "dateUpdated": "2026-08-25T15:19:32.286Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-08-25T01:30:39.451Z" }, "datePublic": "2026-08-11T00:00:00.000Z", "title": "NLTK before 3.10.0 Remote Code Execution via Unsafe Pickle Deserialization", "descriptions": [ { "lang": "en", "value": "NLTK before 3.10.0 (affected versions <=3.9.4) contains an unsafe pickle deserialization vulnerability in the TransitionParser.parse() method (nltk/parse/transitionparser.py). The method calls pickle_load() with the default restricted=False, routing deserialization through WarningUnpickler, which does not override find_class() and therefore permits arbitrary class resolution. When an application loads an attacker-crafted model file, embedded pickle gadget chains execute arbitrary Python code with the privileges of the user running the application. NLTK provides a RestrictedUnpickler for safe deserialization, but it is not used by production code paths. Fixed in 3.10.0." } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "description": "Deserialization of Untrusted Data", "cweId": "CWE-502", "type": "CWE" } ] } ], "affected": [ { "vendor": "nltk", "product": "nltk", "defaultStatus": "unaffected", "packageURL": "pkg:pypi/nltk", "versions": [ { "version": "0", "status": "affected", "versionType": "semver", "lessThan": "3.10.0" }, { "version": "3.10.0", "status": "unaffected", "versionType": "semver" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*", "versionEndExcluding": "3.10.0" } ] } ] } ], "metrics": [ { "format": "CVSS", "cvssV4_0": { "version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "subAvailabilityImpact": "HIGH", "baseScore": 9.4, "baseSeverity": "CRITICAL" } }, { "format": "CVSS", "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH", "baseScore": 9.6, "baseSeverity": "CRITICAL" } } ], "references": [ { "url": "https://github.com/nltk/nltk/security/advisories/GHSA-rhp5-r9x4-f5g2", "tags": [ "vendor-advisory" ], "name": "GitHub Security Advisory (GHSA-rhp5-r9x4-f5g2)" }, { "name": "VulnCheck Advisory: NLTK before 3.10.0 Remote Code Execution via Unsafe Pickle Deserialization", "tags": [ "third-party-advisory" ], "url": "https://www.vulncheck.com/advisories/nltk-before-remote-code-execution-via-unsafe-pickle-deserialization" } ], "credits": [ { "lang": "en", "value": "ekaf", "type": "analyst" } ], "x_generator": { "engine": "vulncheck-endgame" } }, "adp": [ { "references": [ { "url": "https://github.com/nltk/nltk/security/advisories/GHSA-rhp5-r9x4-f5g2", "tags": [ "exploit" ] } ], "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-08-25T15:19:21.370761Z", "id": "CVE-2026-78683", "options": [ { "Exploitation": "poc" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-08-25T15:19:32.286Z" } } ] } }