CVE-2024-37893 MFA bypass in oauth flow in Firefly III

What is CVE-2024-37893?

CVE-2024-37893 is a medium-severity authentication bypass vulnerability in firefly-iii, published on 17 Jun 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Firefly III is a free and open source personal finance manager. In affected versions an MFA bypass in the Firefly III OAuth flow may allow malicious users to bypass the MFA-check. This allows malicious users to use password spraying to gain access to Firefly III data using passwords stolen from other sources. As OAuth applications are easily enumerable using an incrementing id, an attacker could try sign an OAuth application up to a users profile quite easily if they have created one. The attacker would also need to know the victims username and password. This problem has been patched in Firefly III v6.1.17 and up. Users are advised to upgrade. Users unable to upgrade should Use a unique password for their Firefly III instance and store their password securely, i.e. in a password manager.

Weakness: CWE-288, CWE-287

Which versions are affected by CVE-2024-37893?

2 open source packages ship an affected version, including grumpydictator/firefly-iii.

How do I fix CVE-2024-37893?

Upgrade grumpydictator/firefly-iii to 6.1.17 or later.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2024-37893 being exploited?

There is no known exploitation of CVE-2024-37893 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-4gm4-c4mh-4p7w.