What’s Vulnerable › Vulnerabilities

CVE-2021-3828: Inefficient Regular Expression Complexity in nltk/nltk

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-09-27 · updated 2026-06-17
• Weakness: CWE-1333

Description

nltk is vulnerable to Inefficient Regular Expression Complexity

Affected products

• nltk: through 3.6.3

References

• https://github.com/nltk/nltk/commit/277711ab1dec729e626b27aab6fa35ea5efbd7e6
• https://huntr.dev/bounties/d19aed43-75bc-4a03-91a0-4d0bb516bc32
• https://github.com/nltk/nltk/commit/277711ab1dec729e626b27aab6fa35ea5efbd7e6
• https://huntr.dev/bounties/d19aed43-75bc-4a03-91a0-4d0bb516bc32

Get alerted when CVE-2021-3828 or the next vulnerability affects your stack