HOMEVULNERABILITIESCVE-2020-27304
CRITICAL

CVE-2020-27304

CWE-23Published: October 21, 2021· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official 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

NVD Source

Technical Analysis

CVE-2020-27304 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

civetweb_project1 product(s)
civetweb
siemens1 product(s)
sinec infrastructure network services
Source: NVD CPE · 2 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

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

All References (8)

→
https://cert-portal.siemens.com/productcert/pdf/ssa-222547.pdf
→
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdfPatch · Third Party Advisory
→
https://groups.google.com/g/civetweb/c/yPBxNXdGgJQMailing List · Third Party Advisory
→
https://jfrog.com/blog/cve-2020-27304-rce-via-directory-traversal-in-civetweb-http-server/Exploit · Third Party Advisory
→
https://cert-portal.siemens.com/productcert/pdf/ssa-222547.pdf
→
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdfPatch · Third Party Advisory
→
https://groups.google.com/g/civetweb/c/yPBxNXdGgJQMailing List · Third Party Advisory
→
https://jfrog.com/blog/cve-2020-27304-rce-via-directory-traversal-in-civetweb-http-server/Exploit · Third Party Advisory

Quick Facts

CVE IDCVE-2020-27304
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-23
CISA KEVNo
Affected2 vendor(s)
PublishedOct 21, 2021

Related CVEs (CWE-23)

CVE-2026-52813
KEV10.0
CVE-2023-3941
10.0
CVE-2026-8326
10.0
CVE-2026-33494
10.0
CVE-2012-6069
10.0
CVE-2024-47051
9.9

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-27304 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
← All Vulnerabilities·Search for CVE-2020-27304·NVD