Skip to content
Critical RCE Vulnerabilities Disclosed in NLTK Toolkit

Critical RCE Vulnerabilities Disclosed in NLTK Toolkit

First seen 26 Aug 2026, 06:53 UTC • •

Article Content

Browse articles
ThreatCluster AI
ThreatCluster •August 27, 2026 at 06:40 UTC
  • •CVE-2026-79657 allows RCE via unsafe pickle deserialization in NLTK.
  • •Four CVEs disclosed, with CVSS scores ranging from 7.5 to 9.8.
  • •Immediate upgrade to NLTK 3.10.3 is recommended to mitigate risks.

A mass disclosure of four CVEs affecting NLTK versions before 3.10.3 was announced, with CVE-2026-79657 rated at CVSS 9.8. This critical vulnerability allows remote code execution through unsafe pickle deserialization, where allowlisted loaders trust entire module namespaces. Attackers can exploit this by crafting malicious pickle payloads that invoke dangerous functions during model loading. Other vulnerabilities include CVE-2026-78683 (9.6), CVE-2026-78681 (8.7), and CVE-2026-78682 (7.5), impacting file disclosure and denial of service. No active exploitation has been reported at the time of publication, but users are urged to update to NLTK 3.10.3 immediately. The vulnerabilities affect a wide range of NLP/ML pipelines and security tools that utilize NLTK. Patches for all vulnerabilities are available in the fixed version.

Start a free Starter trial for enhanced analysis

Ask AI about this cluster

Updated 46d ago How this analysis works

Timeline

2026-08-25
CVE-2026-79657 published
CVE-2026-79657 disclosed, revealing a critical RCE vulnerability in NLTK's pickle loaders.
Feedly
2026-08-25
CVE-2026-78683 published
CVE-2026-78683 disclosed, detailing another critical deserialization vulnerability in NLTK.
Feedly
2026-08-25
CVE-2026-78681 published
CVE-2026-78681 published, highlighting an XML entity expansion DoS vulnerability.
Feedly
2026-08-25
CVE-2026-78682 published
CVE-2026-78682 disclosed, revealing SSRF vulnerability via proxy handler in NLTK.
Feedly
2026-08-26
NLTK mass disclosure announced
NLTK disclosed four CVEs, urging users to upgrade to version 3.10.3 to mitigate risks.
threataft.com

More articles in this cluster (3)

Following this threat?

Track CVE-2026-78681 in your own feed — you're alerted when they show up in new reporting, leak sites or exploitation.

Free account · no card needed