CVE-2021-4005Network attack vector

Two-factor authentication disablement via tokenless GET request

Published Dec 4, 2021 · Updated Aug 3, 2024

Cross-site request forgery in Firefly III before 5.6.6 allows remote attackers to disable a target user's two-factor authentication. The profile view renders the profile.delete-code action as a GET link without a CSRF token, so a browser can submit the state-changing request cross-origin. Exploitation requires a signed-in user with two-factor authentication enabled to visit attacker-controlled content; the result is removal of that account protection.

CVSS severity4.3
Medium
EPSS probability0.43%
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 Firefly III before 5.6.6 allows remote attackers to disable a target user's two-factor authentication. The profile view renders the profile.delete-code action as a GET link without a CSRF token, so a browser can submit the state-changing request cross-origin. Exploitation requires a signed-in user with two-factor authentication enabled to visit attacker-controlled content; the result is removal of that account protection.

The record

CVE
CVE-2021-4005
Published
Dec 4, 2021
Updated
Aug 3, 2024
Vendor
Firefly III
Product
Firefly III
Classifications
CWE-352, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 4, 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 <5.6.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Firefly III · Firefly IIIversion=unspecified <5.6.6

Published CVSS scores

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

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

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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)
T1204.001User Execution: Malicious Link

Public exploit references

No public exploit references are available in this record.

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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