Staging Environment: Content and features may be unstable or change without notice.
Advisory details: gitlab / pypi/nltk/CVE-2026-78682
Advisory ID gitlab/pypi/nltk/CVE-2026-78682
Aliases CVE-2026-78682
GHSA-6ww7-3frv-cqxh
Summary NLTK: pathsec SSRF protection can be bypassed when a proxy is configured Current NLTK source reopens SSRF in proxied environments. `pathsec.urlopen()` validates the requested hostname locally, but once proxy inheritance is enabled the real fetch is performed by the proxy rather than by the validated direct-connect socket path.
Status Published
Exploitability 0.5
Weighted Severity 0.0
Risk
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (4)
CWE-918 Server-Side Request Forgery (SSRF)
CWE-441 Unintended Proxy or Intermediary ('Confused Deputy')
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv3.1 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/pypi/nltk/CVE-2026-78682.yml
Reference id Reference type URL
https://github.com/nltk/nltk/commit/767333a005a1cd3d82d2029215f2dbe66a5844d9
https://github.com/nltk/nltk/releases/tag/v3.10.3
https://github.com/nltk/nltk/security/advisories/GHSA-6ww7-3frv-cqxh
https://github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3733.yaml
https://www.vulncheck.com/advisories/nltk-before-ssrf-protection-bypass-via-proxy
CVE-2026-78682 https://nvd.nist.gov/vuln/detail/CVE-2026-78682
GHSA-6ww7-3frv-cqxh https://github.com/advisories/GHSA-6ww7-3frv-cqxh
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Found at https://gitlab.com/gitlab-org/advisories-community/-/blob/main/pypi/nltk/CVE-2026-78682.yml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

There are no SSVC decisions available.