CVE-2021-4033Network attack vector

Unauthorized invoice creation via reusable CSRF tokens

Published Dec 9, 2021 · Updated Aug 3, 2024

Cross-site request forgery in Kimai before 1.16.7 allows remote attackers to create invoices through a crafted request in an authenticated user's browser. InvoiceController::createInvoiceAction accepts the invoice.create token without invalidating it, while shared search handling retains the token in query parameters. Exploitation requires interaction by a logged-in user who can create invoices, and the resulting action writes an unauthorized invoice under that user's session.

CVSS severity6.5
Medium
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site request forgery in Kimai before 1.16.7 allows remote attackers to create invoices through a crafted request in an authenticated user's browser. InvoiceController::createInvoiceAction accepts the invoice.create token without invalidating it, while shared search handling retains the token in query parameters. Exploitation requires interaction by a logged-in user who can create invoices, and the resulting action writes an unauthorized invoice under that user's session.

The record

CVE
CVE-2021-4033
Published
Dec 9, 2021
Updated
Aug 3, 2024
Vendor
Kevin Papst
Product
Kimai
Classifications
CWE-352, CAPEC-62, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 9, 2021CVE 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 <1.16.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Kevin Papst · Kimaiversion=unspecified <1.16.7

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.5huntr.devCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-352Cross-Site Request Forgery (CSRF)
CAPEC-62Cross Site Request Forgery
T1204.001User Execution: Malicious Link

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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