What’s Vulnerable › Vulnerabilities

CVE-2021-23354: Regular Expression Denial of Service (ReDoS)

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-03-12 · updated 2026-06-17
• Weakness: CWE-1333

Description

The package printf before 0.6.1 are vulnerable to Regular Expression Denial of Service (ReDoS) via the regex string /\%(?:\(([\w_.]+)\)|([1-9]\d*)\$)?([0 +\-\]*)(\*|\d+)?(\.)?(\*|\d+)?[hlL]?([\%bscdeEfFgGioOuxX])/g in lib/printf.js. The vulnerable regular expression has cubic worst-case time complexity.

Affected products

• printf: before 0.6.1 — fixed in 0.6.1

How to fix

Upgrade to a fixed version: printf 0.6.1. Check the vendor advisory for mitigations.

References

• https://github.com/adaltas/node-printf/issues/31
• https://github.com/adaltas/node-printf/pull/32
• https://snyk.io/vuln/SNYK-JS-PRINTF-1072096
• https://github.com/adaltas/node-printf/issues/31
• https://github.com/adaltas/node-printf/pull/32
• https://snyk.io/vuln/SNYK-JS-PRINTF-1072096

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