What’s Vulnerable › Vulnerabilities

CVE-2020-27304

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-10-21 · updated 2026-06-17
• Weakness: CWE-23

Description

The CivetWeb web library does not validate uploaded filepaths when running on an OS other than Windows, when using the built-in HTTP form-based file upload mechanism, via the mg_handle_form_request API. Web applications that use the file upload form handler, and use parts of the user-controlled filename in the output path, are susceptible to directory traversal

Affected products

• CivetWeb: from 1.8 before 1.15 — fixed in 1.15
• Siemens Sinec Infrastructure Network Services: before 1.0.1.1 — fixed in 1.0.1.1

How to fix

Upgrade to a fixed version: CivetWeb 1.15; Siemens Sinec Infrastructure Network Services 1.0.1.1. Check the vendor advisory for mitigations.

References

• https://cert-portal.siemens.com/productcert/pdf/ssa-222547.pdf
• https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
• https://groups.google.com/g/civetweb/c/yPBxNXdGgJQ
• https://jfrog.com/blog/cve-2020-27304-rce-via-directory-traversal-in-civetweb-http-server/
• https://cert-portal.siemens.com/productcert/pdf/ssa-222547.pdf
• https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
• https://groups.google.com/g/civetweb/c/yPBxNXdGgJQ
• https://jfrog.com/blog/cve-2020-27304-rce-via-directory-traversal-in-civetweb-http-server/

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