CVE-2021-4080Network attack vector

Authenticated dangerous-file upload via missing MIME validation

Published Jan 12, 2022 · Updated Aug 3, 2024

Unrestricted file upload in Crater before 6.0.0 allows remote authenticated users to store dangerous files through administrative upload forms. The company-logo, avatar, and expense-receipt handlers accepted uploaded or Base64-encoded content without checking its detected MIME type against an allowlist. A low-privileged account can reach these network handlers without further user interaction, allowing PHP or other dangerous content to affect stored data and service integrity.

CVSS severity8.8
High
EPSS probability1.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unrestricted file upload in Crater before 6.0.0 allows remote authenticated users to store dangerous files through administrative upload forms. The company-logo, avatar, and expense-receipt handlers accepted uploaded or Base64-encoded content without checking its detected MIME type against an allowlist. A low-privileged account can reach these network handlers without further user interaction, allowing PHP or other dangerous content to affect stored data and service integrity.

The record

CVE
CVE-2021-4080
Published
Jan 12, 2022
Updated
Aug 3, 2024
Vendor
Crater Invoice, Inc.
Product
Crater
Classifications
CWE-434, T1105
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 12, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=unspecified <6.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Crater Invoice, Inc. · Craterversion=unspecified <6.0.0

Published CVSS scores

8.8GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1105Ingress Tool Transfer

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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