CVE-2021-3663

Improper Restriction of Excessive Authentication Attempts in firefly-iii/firefly-iii

5.3 MediumFix available

firefly-iii is vulnerable to Improper Restriction of Excessive Authentication Attempts

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: Low
Availability: Low

Exploit likelihood

0.71%Up 0.1 points since Jul 26, 2021

What each source reports

CVE List Score used 5.3

Improper Restriction of Excessive Authentication Attempts in firefly-iii/firefly-iii

firefly-iii is vulnerable to Improper Restriction of Excessive Authentication Attempts

Record: CVE-2021-3663
CVSS 3.0: 5.3 MediumCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
Weakness: CWE-307
Updated: 2026-11-02

EUVDEUVD-2021-1572 5.3

firefly-iii is vulnerable to Improper Restriction of Excessive Authentication Attempts

Record: EUVD-2021-1572
CVSS 3.0: 5.3 MediumCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
Updated: 2026-11-03

GitHub AdvisoriesGHSA-56cx-wf47-hx7w 5.3

No Restriction of Excessive Authentication Attempts in Firefly III

firefly-iii is vulnerable to Improper Lack of Restriction of Excessive Authentication Attempts

Record: GHSA-56cx-wf47-hx7w
CVSS 3.0: 5.3 MediumCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
Weakness: CWE-307
Updated: 2026-11-02

NVD 7.5

firefly-iii is vulnerable to Improper Restriction of Excessive Authentication Attempts

Record: CVE-2021-3663
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS 3.0: 5.3 MediumCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
CVSS 2.0: 5.0 MediumAV:N/AC:L/Au:N/C:P/I:N/A:N
Weakness: CWE-307
Updated: 2026-11-02

OSV 7.5

firefly-iii is vulnerable to Improper Restriction of Excessive Authentication Attempts

Record: CVE-2021-3663
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated: 2026-11-02

OSVGHSA-56cx-wf47-hx7w 5.3

No Restriction of Excessive Authentication Attempts in Firefly III

firefly-iii is vulnerable to Improper Lack of Restriction of Excessive Authentication Attempts

Record: GHSA-56cx-wf47-hx7w
CVSS 3.0: 5.3 MediumCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
Weakness: CWE-307
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`grumpydictator/firefly-iii` Packagist	before 5.5.13	5.5.13
`grumpydictator/firefly-iii` Packagist	before 5.5.13, plus listed versions 3.0.03.0.13.0.23.0.33.1 Show 45 moreShow less 3.1.13.1.23.1.33.1.43.1.53.1.63.103.10.13.10.23.10.33.10.43.2.03.2.13.2.23.2.33.2.43.2.53.33.3.13.3.23.3.33.3.43.3.53.3.63.3.73.3.83.3.93.43.4.0.13.4.0.103.4.0.23.4.0.33.4.0.43.4.0.53.4.0.63.4.0.73.4.0.83.4.0.93.4.13.4.103.4.113.4.23.4.33.4.43.4.4.1	5.5.13

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-3663 is a medium vulnerability (CVSS 5.3) in Firefly-iii Firefly-iii/firefly-iii, published July 25, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.71%, the 53rd percentile. Fixed in grumpydictator/firefly-iii 5.5.13.

References

This page doesn't list everything

Left out here: 193 versions. The JSON record has them.