Summary
C5 Firefly III CSV Injection.
CSV injection is a vulnerability where untrusted user input in CSV files can lead to unauthorized access or data manipulation.
In my subsequent testing of the application.
Details
I discovered that there is an option to "Export Data" from the web app to your personal computer, which exports a "csv" file that can be opened with Excel software that supports macros.
P.S
I discovered that the web application's is offering a demo-site that anyone may access to play with the web application. So, there's a chance that someone will export the data (CVS) from the demo site and execute it on their PC, giving the malicious actor a complete control over their machine. (if a user enters a malicious payload to the website).
PoC
You can check out my vulnerability report if you need more details/PoC with screenshots: (removed by JC5)
Addendum by JC5, the developer of Firefly III
There is zero impact on normal users, even on vulnerable versions.
Impact
An attacker can exploit this by entering a specially crafted payload to one of the fields, and when a user export the csv file using the "Export Data" function, the attacker can potentiality can RCE.
GHSA-29W6-C52G-M8JC has a CVSS score of 4.0 (Medium). The vector is requires local access, high privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (6.1.7); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is GHSA-29W6-C52G-M8JC? GHSA-29W6-C52G-M8JC is a medium-severity security vulnerability in grumpydictator/firefly-iii (composer), affecting versions < 6.1.7. It is fixed in 6.1.7.
- How severe is GHSA-29W6-C52G-M8JC? GHSA-29W6-C52G-M8JC has a CVSS score of 4.0 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of grumpydictator/firefly-iii are affected by GHSA-29W6-C52G-M8JC? grumpydictator/firefly-iii (composer) versions < 6.1.7 is affected.
- Is there a fix for GHSA-29W6-C52G-M8JC? Yes. GHSA-29W6-C52G-M8JC is fixed in 6.1.7. Upgrade to this version or later.
- Is GHSA-29W6-C52G-M8JC exploitable, and should I be worried? Whether GHSA-29W6-C52G-M8JC is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-29W6-C52G-M8JC is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-29W6-C52G-M8JC? Upgrade
grumpydictator/firefly-iiito 6.1.7 or later.