CVE-2026-78682 (GCVE-0-2026-78682)

Vulnerability from cvelistv5 – Published: 2026-08-25 01:30 – Updated: 2026-10-08 15:25
VLAI
Title
NLTK before 3.10.3 SSRF Protection Bypass via Proxy
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 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.
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-25 15:23 UTC
CWE
  • CWE-918 - Server-Side Request Forgery (SSRF)
Assigner
VulnCheck CNA under the mitre root
CNA scorecard B 84/100 over 7808 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
nltk nltk Affected: 0 , < 3.10.3 (semver)
Unaffected: 3.10.3 (semver)
    cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*
Create a notification for this product.
Date Public
2026-08-11 00:00
Credits
Show details on NVD website

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How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Events included in the timeline

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    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.