How severe is CVE-2025-71408?

CVE-2025-71408 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-71408 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-71408?

CVE-2025-71408 affects Nltk. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-71408?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2025-71408 published?

CVE-2025-71408 was published on 2026-07-24 and last updated on 2026-08-10.

CVE-2025-71408

CVE-2025-71408 is a high-severity vulnerability in Nltk with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-95.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v4: 8.5
EPSS exploit prediction: 0% (8th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-95
Affected product: Nltk
Published: 2026-07-24
Last modified: 2026-08-10

Description

NLTK (Natural Language Toolkit) before version 3.9.3 contains an eval injection vulnerability in the nltk.collocations module that allows an attacker who controls command-line arguments to execute arbitrary Python code. When collocations.py is invoked directly, the __main__ block passes command-line arguments directly to eval() as suffixes of BigramAssocMeasures without allowlist validation or sanitization, enabling an attacker to supply a Python expression that escapes the intended attribute lookup and executes arbitrary code including OS commands via the os module.

Frequently asked questions

What is CVE-2025-71408?: NLTK (Natural Language Toolkit) before version 3.9.3 contains an eval injection vulnerability in the nltk.collocations module that allows an attacker who controls command-line arguments to execute arbitrary Python code. When collocations.py is invoked directly, the __main__ block passes command-line arguments directly to eval() as suffixes of BigramAssocMeasures without allowlist validation or sanitization, enabling an attacker to supply a Python expression that escapes the intended attribute lookup and executes arbitrary code including OS commands via the os module.
How severe is CVE-2025-71408?: CVE-2025-71408 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-71408 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-71408?: CVE-2025-71408 affects Nltk. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-71408?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2025-71408 published?: CVE-2025-71408 was published on 2026-07-24 and last updated on 2026-08-10.

References

Affected products (1)

cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*

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