A Server-Side Request Forgery (SSRF) vulnerability exists in nltk/nltk versions 3.9.4 and the current develop branch. The `nltk.pathsec.validate_network_url()` function, intended to prevent SSRF by rejecting internal network addresses, fails to reject IPs in the RFC 6598 shared address space (`100.64.0.0/10`). This occurs because Python's `ipaddress` module does not classify such addresses as `is_private` or `is_global`, and the current guard only checks `is_private` and a few explicit categories. An attacker who can influence a URL passed to NLTK's network-loading helpers can exploit this vulnerability to make a strict-mode application send requests to shared-address-space hosts, potentially exposing non-public infrastructure reachable from the application host. The impact is limited to SSRF-style confidentiality exposure, with no code execution claimed.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - A Server-Side Request Forgery (SSRF) vulnerability exists in nltk/nltk versions 3.9.4 and the current
    develop branch. The `nltk.pathsec.validate_network_url()` function, intended to prevent SSRF by rejecting
    internal network addresses, fails to reject IPs in the RFC 6598 shared address space (`100.64.0.0/10`).
    This occurs because Python's `ipaddress` module does not classify such addresses as `is_private` or
    `is_global`, and the current guard only checks `is_private` and a few explicit categories. An attacker who
    can influence a URL passed to NLTK's network-loading helpers can exploit this vulnerability to make a
    strict-mode application send requests to shared-address-space hosts, potentially exposing non-public
    infrastructure reachable from the application host. The impact is limited to SSRF-style confidentiality
    exposure, with no code execution claimed. (CVE-2026-12372)

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - A Server-Side Request Forgery (SSRF) vulnerability exists in nltk/nltk versions 3.9.4 and the current     develop branch. The `nltk.pathsec.validate_network_url()` function, intended to prevent SSRF by rejecting     internal network addresses, fails to reject IPs in the RFC 6598 shared address space (`100.64.0.0/10`).
    This occurs because Python's `ipaddress` module does not classify such addresses as `is_private` or     `is_global`, and the current guard only checks `is_private` and a few explicit categories. An attacker who     can influence a URL passed to NLTK's network-loading helpers can exploit this vulnerability to make a     strict-mode application send requests to shared-address-space hosts, potentially exposing non-public     infrastructure reachable from the application host. The impact is limited to SSRF-style confidentiality     exposure, with no code execution claimed. (CVE-2026-12372)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
472828	Echo: nltk: security update to 3.10.0	Tenable Cloud Security	Echo Local Security Checks	Local	low
472828	Echo: nltk: security update to 3.10.0	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	low
471978	SCA: security update for nltk (GHSA-2jhm-w3mp-jcwr)	Tenable Cloud Security	SCA Checks	Local	low
471978	SCA: security update for nltk (GHSA-2jhm-w3mp-jcwr)	Tenable Self-Hosted Container Security	SCA Checks	Local	low
333618	Linux Distros Unpatched Vulnerability : CVE-2026-12372	Nessus	Misc.	Local	low

Detections

Analytics

CVE-2026-12372

low

Tenable Plugins

low

low

low

low

low