CVE-2020-27304
CRITICALEPSS 88th pctlDescription
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
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Elevated risk: more likely to be exploited than 88% of all known CVEs.
References
Related Vulnerabilities
Other CWE-23 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-27199 | High | 7.3 | 100% | KEV + Ransom | Fix |
| CVE-2020-5410 | High | 7.5 | 96% | KEV | Fix |
| CVE-2021-40870 | Critical | 9.8 | 93% | KEV | Fix |
| CVE-2025-64446 | Critical | 9.8 | 92% | KEV | Fix |
| CVE-2020-5405 | Medium | 6.5 | 69% | - | Fix |
| CVE-2025-55752 | High | 7.5 | 67% | - | Fix |
Common questions
How do I fix CVE-2020-27304?
Upgrade civetweb on debian 12 to 1.15+dfsg-1 or later.
Is CVE-2020-27304 being actively exploited?
Not that we know of. CVE-2020-27304 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 3.2% is the estimated probability that it will be exploited in the next 30 days. That is higher than 88% of all scored CVEs.
How severe is CVE-2020-27304?
CVE-2020-27304 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2020-27304 affect?
Published advisories record a fix for civetweb (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-17.