Executive brief
TaxHacker is a self-hosted AI accounting application that analyzes receipts and transactions. An unauthenticated attacker can exploit a flaw in the LLM provider testing function to make the server perform HTTP requests to arbitrary internal or external URLs, and retrieve the responses. This could allow an attacker to probe internal networks, access cloud metadata services, or read sensitive data from internal APIs.
Technical details
The testLLMProviderAction server action lacks authentication and input validation on the baseUrl parameter. An attacker can invoke the action directly via the Next-Action header with a malicious baseUrl, causing the server to make an HTTP POST request to that URL. Connection errors and raw response bodies are echoed back to the attacker, enabling full SSRF with response exfiltration. The vulnerability affects versions up to 0.8.5 in both self-hosted and SaaS deployments, though self-hosted mode is fully exploitable without a session.
Affected products
- vas3k TaxHacker up to 0.8.5
Timeline
- 2026-08-26: disclosed: Reported via GitHub issue #187
- 2026-09-20: advisory: CVE-2026-94040 published on NVD