What’s Vulnerable › Vulnerabilities

CVE-2021-23406: Remote Code Execution (RCE)

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-08-24 · updated 2026-06-17

Description

This affects the package pac-resolver before 5.0.0. This can occur when used with untrusted input, due to unsafe PAC file handling. **NOTE:** The fix for this vulnerability is applied in the node-degenerator library, a dependency written by the same maintainer.

Affected products

• pac-resolver: before 5.0.0 — fixed in 5.0.0

How to fix

Upgrade to a fixed version: pac-resolver 5.0.0. Check the vendor advisory for mitigations.

References

• https://github.com/TooTallNate/node-degenerator/commit/9d25bb67d957bc2e5425fea7bf7a58b3fc64ff9e
• https://github.com/TooTallNate/node-degenerator/commit/ccc3445354135398b6eb1a04c7d27c13b833f2d5
• https://github.com/TooTallNate/node-pac-resolver/releases/tag/5.0.0
• https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1568506
• https://snyk.io/vuln/SNYK-JS-PACRESOLVER-1564857
• https://github.com/TooTallNate/node-degenerator/commit/9d25bb67d957bc2e5425fea7bf7a58b3fc64ff9e
• https://github.com/TooTallNate/node-degenerator/commit/ccc3445354135398b6eb1a04c7d27c13b833f2d5
• https://github.com/TooTallNate/node-pac-resolver/releases/tag/5.0.0
• https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1568506
• https://snyk.io/vuln/SNYK-JS-PACRESOLVER-1564857

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