{"id":"CVE-2026-78682","title":"NLTK before 3.10.3 contains a server-side request forgery vulnerability in nltk.pathsec.urlopen (and callers nltk.data.load, nltk.downloader.Downloader.index/download) when an HTTP proxy is configured","summary":"NLTK before 3.10.3 contains a server-side request forgery vulnerability in nltk.pathsec.urlopen (and callers nltk.data.load, nltk.downloader.Downloader.index/download) when an HTTP proxy is configured. pathsec.urlopen validates the reque…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","cwe":["CWE-918","CWE-441"],"vendor":"nltk","product":"nltk","affected":["nltk < 3.10.3"],"patched":["nltk 3.10.3"],"published":"2026-08-25","updated":"2026-10-12","sourceUpdated":"2026-10-12T21:10:00.227","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-78682","references":[{"url":"https://github.com/nltk/nltk/security/advisories/GHSA-6ww7-3frv-cqxh","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/nltk-before-ssrf-protection-bypass-via-proxy","label":"disclosure@vulncheck.com"},{"url":"https://github.com/nltk/nltk/security/advisories/GHSA-6ww7-3frv-cqxh","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-78682.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-78682"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2523191"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-78682"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-78682"},{"url":"https://access.redhat.com/errata/RHSA-2026:73987"},{"url":"https://github.com/nltk/nltk/commit/767333a005a1cd3d82d2029215f2dbe66a5844d9"},{"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-2026-3733.yaml"},{"url":"https://github.com/advisories/GHSA-6ww7-3frv-cqxh"},{"url":"https://access.redhat.com/errata/RHSA-2026:84734"}],"tags":["nvd","cve.org","exploit-available","csaf","vex","red-hat","osv","pip","ghsa"],"epss":0.00435,"epssPercentile":0.37575,"aliases":["GHSA-6ww7-3frv-cqxh","PYSEC-2026-3733"],"ecosystem":"pip","exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"partial","timestamp":"2026-08-25T15:23:28.158842Z"},"ingestedAt":"2026-09-02T19:31:24.306Z","slug":"CVE-2026-78682","body":"## Overview\n\nNLTK before 3.10.3 contains a server-side request forgery vulnerability in nltk.pathsec.urlopen (and callers nltk.data.load, nltk.downloader.Downloader.index/download) when an HTTP proxy is configured. pathsec.urlopen validates the requested hostname locally, but proxy-handler inheritance disables the safe HTTP/HTTPS handlers so the actual fetch is performed by the proxy against a destination that is never re-validated. An attacker can supply a validated public URL that the proxy forwards to an internal loopback-only service, allowing disclosure of internal HTTP resources, loading of forged downloader indexes, and installation of attacker-chosen package content.\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-2026-78682)\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-6ww7-3frv-cqxh\n\n## Vendor advisories\n\n- **RHSA-2026:73987** · Red Hat · fixed in: Red Hat OpenShift AI 3.3 · released 2026-09-30 · [advisory](https://access.redhat.com/errata/RHSA-2026:73987)\n- **Red Hat VEX** · Important · 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 2026-10-19 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-78682.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":"midnight","depthScore":53,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":218168,"id":"CVE-2026-78682","ts":1791478458298,"field":"exploit_available","old":"false","new":"true"},{"seq":5479,"id":"CVE-2026-78682","ts":1788887288565,"field":"cvss","old":null,"new":"7.5"},{"seq":5478,"id":"CVE-2026-78682","ts":1788887288565,"field":"severity","old":"none","new":"high"},{"seq":4361,"id":"CVE-2026-78682","ts":1788886401285,"field":"cvss","old":"7.5","new":null},{"seq":4360,"id":"CVE-2026-78682","ts":1788886401285,"field":"severity","old":"high","new":"none"},{"seq":3231,"id":"CVE-2026-78682","ts":1788883135158,"field":"cvss","old":null,"new":"7.5"},{"seq":3230,"id":"CVE-2026-78682","ts":1788883135158,"field":"severity","old":"none","new":"high"}]}