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CVE-2021-23424 (GCVE-0-2021-23424)

Vulnerability from cvelistv5 – Published: 2021-08-18 16:15 – Updated: 2024-09-16 17:38
VLAI
Title
Regular Expression Denial of Service (ReDoS)
Summary
This affects all versions of package ansi-html. If an attacker provides a malicious string, it will get stuck processing the input for an extremely long time.
CWE
  • Regular Expression Denial of Service (ReDoS)
Impacted products
Vendor Product Version CPE status
n/a ansi-html Affected: 0 , < unspecified (custom)
Date Public
2021-08-18 00:00
Show details on NVD website

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}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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