CVE-2020-27304Public exploitNetwork attack vector

Remote file write via unsanitized upload filename

Published Oct 21, 2021 · Updated Aug 4, 2024

Directory traversal in CivetWeb 1.8 through 1.14 allows remote attackers to write files via crafted upload filenames. The mg_handle_form_request upload handler passes a client-supplied filename into the output path without sanitizing path components on non-Windows systems. Exploitation requires an application that uses the built-in form upload handler and incorporates the filename into its destination; a crafted request can write outside the intended directory and potentially affect confidentiality, integrity, and availability.

CVSS severity9.8
Critical
EPSS probability3.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Directory traversal in CivetWeb 1.8 through 1.14 allows remote attackers to write files via crafted upload filenames. The mg_handle_form_request upload handler passes a client-supplied filename into the output path without sanitizing path components on non-Windows systems. Exploitation requires an application that uses the built-in form upload handler and incorporates the filename into its destination; a crafted request can write outside the intended directory and potentially affect confidentiality, integrity, and availability.

The record

CVE
CVE-2020-27304
Published
Oct 21, 2021
Updated
Aug 4, 2024
Vendor
CivetWeb
Product
CivetWeb
Classifications
CWE-23, CWE-22, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 21, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.8 <unspecified

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

CivetWeb · CivetWebversion=1.8 <unspecified

Published CVSS scores

7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-23Relative Path Traversal
CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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