CVE-2026-78682Public exploitNetwork attack vector

Internal resource disclosure via unvalidated proxy egress

Published Aug 25, 2026 · Updated Aug 25, 2026

Server-side request forgery in NLTK before 3.10.3 allows remote attackers to read internal HTTP resources through a configured proxy. In nltk.pathsec.urlopen, inherited ProxyHandler objects disable the safe HTTP handlers, so the proxy fetches a destination that NLTK never revalidates. Exploitation requires an attacker-influenced URL to reach a proxy-enabled NLTK caller and can also load forged downloader indexes or install attacker-chosen package content.

CVSS severity8.7
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Server-side request forgery in NLTK before 3.10.3 allows remote attackers to read internal HTTP resources through a configured proxy. In nltk.pathsec.urlopen, inherited ProxyHandler objects disable the safe HTTP handlers, so the proxy fetches a destination that NLTK never revalidates. Exploitation requires an attacker-influenced URL to reach a proxy-enabled NLTK caller and can also load forged downloader indexes or install attacker-chosen package content.

The record

CVE
CVE-2026-78682
Published
Aug 25, 2026
Updated
Aug 25, 2026
Vendor
NLTK Project
Product
NLTK
Classifications
CWE-918, CWE-441
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.10.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

NLTK Project · NLTKversion=0 <3.10.3

Published CVSS scores

8.7GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
CWE-441Unintended Proxy or Intermediary ('Confused Deputy')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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