CVE-2026-71513
HIGHDescription
NLTK before 3.10.3 contains a remote code execution vulnerability in AllowlistUnpickler that validates only the pickle module string and not the global name, allowing attackers to resolve dotted names by attribute traversal to callables outside the allowlisted namespace. Attackers can craft untrusted transition-parser models that execute arbitrary commands when TransitionParser.parse loads the model through allowlisted_pickle_load.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Exploit Intelligence
Moderate risk: more likely to be exploited than 54% of all known CVEs.
References
Related Vulnerabilities
Other CWE-502 (Deserialization of Untrusted Data) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-0669 | High | 7.2 | 100% | KEV + Ransom | Fix |
| CVE-2021-44228 | Critical | 10.0 | 100% | KEV + Ransom | Fix |
| CVE-2021-35464 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
| CVE-2025-53770 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
| CVE-2023-29300 | Critical | 9.8 | 100% | KEV + Ransom | - |
| CVE-2025-59287 | Critical | 9.8 | 100% | KEV | Fix |
Common questions
How do I fix CVE-2026-71513?
Upgrade nltk on debian unstable to 3.10.3-1 or later.
Is CVE-2026-71513 being actively exploited?
Not that we know of. CVE-2026-71513 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.78% is the estimated probability that it will be exploited in the next 30 days. That is higher than 54% of all scored CVEs.
How severe is CVE-2026-71513?
CVE-2026-71513 has a CVSS v3 base score of 8.8, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-71513 affect?
Published advisories record a fix for nltk (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-71513
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-27.