CVE-2021-3900

Cross-Site Request Forgery (CSRF) in firefly-iii/firefly-iii

4.3 Medium

firefly-iii is vulnerable to Cross-Site Request Forgery (CSRF)

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Required

What an attacker can affect

Confidentiality: None
Integrity: Low
Availability: None

Exploit likelihood

0.55%Down 0.1 points since Oct 28, 2021

What each source reports

CVE List Score used 4.3

Cross-Site Request Forgery (CSRF) in firefly-iii/firefly-iii

firefly-iii is vulnerable to Cross-Site Request Forgery (CSRF)

Record: CVE-2021-3900
CVSS 3.0: 4.3 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Weakness: CWE-352
Updated: 2026-11-02

EUVDEUVD-2021-2235 4.3

firefly-iii is vulnerable to Cross-Site Request Forgery (CSRF)

Record: EUVD-2021-2235
CVSS 3.0: 4.3 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Updated: 2026-11-03

GitHub AdvisoriesGHSA-pfj7-w373-gqch 6.5

Cross-Site Request Forgery in firefly-iii

firefly-iii is vulnerable to Cross-Site Request Forgery (CSRF).

Record: GHSA-pfj7-w373-gqch
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Weakness: CWE-352
Updated: 2026-11-02

NVD 6.5

firefly-iii is vulnerable to Cross-Site Request Forgery (CSRF)

Record: CVE-2021-3900
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
CVSS 3.0: 4.3 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
CVSS 2.0: 4.3 MediumAV:N/AC:M/Au:N/C:N/I:P/A:N
Weakness: CWE-352
Updated: 2026-11-02

OSV 6.5

firefly-iii is vulnerable to Cross-Site Request Forgery (CSRF)

Record: CVE-2021-3900
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Updated: 2026-11-02

OSVGHSA-pfj7-w373-gqch 6.5

Cross-Site Request Forgery in firefly-iii

firefly-iii is vulnerable to Cross-Site Request Forgery (CSRF).

Record: GHSA-pfj7-w373-gqch
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Weakness: CWE-352
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`grumpydictator/firefly-iii` Packagist	through 5.6.2	None known
`grumpydictator/firefly-iii` Packagist	through 5.6.2, 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	None known

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-2021-3900 is a medium vulnerability (CVSS 4.3) in Firefly-iii Firefly-iii/firefly-iii, published October 27, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.55%, the 46th percentile. No source names a fixed version.

References

This page doesn't list everything

Left out here: 198 versions. The JSON record has them.