{"id":"CVE-2026-79657","title":"NLTK versions before 3.10.3 contain a remote code execution vulnerability in allowlisted pickle loaders that trust entire module namespaces instead of specific safe callables","summary":"NLTK versions before 3.10.3 contain a remote code execution vulnerability in allowlisted pickle loaders that trust entire module namespaces instead of specific safe callables. Attackers can craft malicious pickle payloads invoking danger…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-502","CWE-693"],"vendor":"nltk","product":"nltk","affected":["nltk < 3.10.3"],"patched":["nltk 3.10.3"],"published":"2026-08-25","updated":"2026-10-08","sourceUpdated":"2026-10-08T16:17:44.427","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-79657","references":[{"url":"https://github.com/nltk/nltk/security/advisories/GHSA-x99w-6fgc-pmfw","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/nltk-before-3.10.3-remote-code-execution-via-unsafe-pickle-deserialization","label":"disclosure@vulncheck.com"},{"url":"https://github.com/nltk/nltk/security/advisories/GHSA-x99w-6fgc-pmfw","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-79657.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-79657"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2523372"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-79657"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-79657"},{"url":"https://github.com/nltk/nltk/commit/c3e37113742a1ebeeb4f2ca58941f320f98805ea"},{"url":"https://github.com/nltk/nltk"},{"url":"https://github.com/nltk/nltk/releases/tag/v3.10.3"},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3735.yaml"},{"url":"https://github.com/advisories/GHSA-x99w-6fgc-pmfw"},{"url":"https://access.redhat.com/errata/RHSA-2026:84734"}],"tags":["nvd","cve.org","exploit-available","csaf","vex","red-hat","osv","pip","ghsa"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"total","timestamp":"2026-08-25T15:58:28.455681Z"},"epss":0.01267,"epssPercentile":0.69612,"aliases":["GHSA-x99w-6fgc-pmfw","PYSEC-2026-3735"],"ecosystem":"pip","scores":{"nvd":9.8,"vendor":8.8},"ingestedAt":"2026-09-02T19:31:24.390Z","slug":"CVE-2026-79657","body":"## Overview\n\nNLTK versions before 3.10.3 contain a remote code execution vulnerability in allowlisted pickle loaders that trust entire module namespaces instead of specific safe callables. Attackers can craft malicious pickle payloads invoking dangerous in-namespace functions like ReppTokenizer._execute and numpy.f2py.crackfortran.myeval through pickle REDUCE to execute arbitrary commands during model or tokenizer artifact loading.\n\n## Affected\n\n- `nltk < 3.10.3`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `nltk 3.10.3`\n\n## Package advisory (CVE-2026-79657)\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-x99w-6fgc-pmfw\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Lightspeed Core, OpenShift Lightspeed, Red Hat Ansible Automation Platform 2 · no fix planned: Red Hat Ansible Automation Platform 2, Lightspeed Core, OpenShift Lightspeed · updated 2026-10-19 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-79657.json)\n- **RHSA-2026:84734** · Red Hat · fixed in: Red Hat OpenShift AI 3.4 · released 2026-10-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:84734)","depth":"abyssal","depthScore":66,"depthScoreParts":{"impact":53.9,"likelihood":0.3,"exploitation":12,"ransomware":0},"changes":[{"seq":218171,"id":"CVE-2026-79657","ts":1791478458702,"field":"exploit_available","old":"false","new":"true"},{"seq":218170,"id":"CVE-2026-79657","ts":1791478458702,"field":"cvss","old":"8.8","new":"9.8"},{"seq":218169,"id":"CVE-2026-79657","ts":1791478458702,"field":"severity","old":"high","new":"critical"},{"seq":214825,"id":"CVE-2026-79657","ts":1790927934390,"field":"cvss","old":"9.8","new":"8.8"},{"seq":214824,"id":"CVE-2026-79657","ts":1790927934390,"field":"severity","old":"critical","new":"high"},{"seq":213482,"id":"CVE-2026-79657","ts":1790754737236,"field":"cvss","old":null,"new":"9.8"},{"seq":8225,"id":"CVE-2026-79657","ts":1788919993439,"field":"severity","old":"none","new":"critical"},{"seq":8034,"id":"CVE-2026-79657","ts":1788919280678,"field":"severity","old":"critical","new":"none"},{"seq":7843,"id":"CVE-2026-79657","ts":1788916353961,"field":"severity","old":"none","new":"critical"},{"seq":7652,"id":"CVE-2026-79657","ts":1788915297381,"field":"severity","old":"critical","new":"none"},{"seq":7461,"id":"CVE-2026-79657","ts":1788912713505,"field":"severity","old":"none","new":"critical"},{"seq":7270,"id":"CVE-2026-79657","ts":1788911331313,"field":"severity","old":"critical","new":"none"},{"seq":7074,"id":"CVE-2026-79657","ts":1788909076736,"field":"severity","old":"none","new":"critical"},{"seq":6886,"id":"CVE-2026-79657","ts":1788907391419,"field":"severity","old":"critical","new":"none"},{"seq":6688,"id":"CVE-2026-79657","ts":1788905443068,"field":"severity","old":"none","new":"critical"},{"seq":6506,"id":"CVE-2026-79657","ts":1788903459631,"field":"severity","old":"critical","new":"none"},{"seq":6296,"id":"CVE-2026-79657","ts":1788901810008,"field":"severity","old":"none","new":"critical"},{"seq":6126,"id":"CVE-2026-79657","ts":1788899562081,"field":"severity","old":"critical","new":"none"},{"seq":5929,"id":"CVE-2026-79657","ts":1788898179237,"field":"severity","old":"none","new":"critical"},{"seq":5818,"id":"CVE-2026-79657","ts":1788895711101,"field":"severity","old":"critical","new":"none"},{"seq":5679,"id":"CVE-2026-79657","ts":1788894533642,"field":"severity","old":"none","new":"critical"},{"seq":5637,"id":"CVE-2026-79657","ts":1788891871395,"field":"severity","old":"critical","new":"none"},{"seq":5570,"id":"CVE-2026-79657","ts":1788888673090,"field":"severity","old":"none","new":"critical"},{"seq":5561,"id":"CVE-2026-79657","ts":1788888071560,"field":"severity","old":"critical","new":"none"},{"seq":5481,"id":"CVE-2026-79657","ts":1788887288740,"field":"severity","old":"none","new":"critical"}]}