CVE-2026-107717 Details
Description
Banks generates meaningful LLM prompts using a simple template language. Prior to 2.5.0, Banks Prompt.chat_messages() attempts to parse every line of rendered template output as ChatMessage JSON. When an application renders untrusted data and passes the returned ChatMessage objects to an LLM provider, attacker-controlled JSON can cross the prompt boundary and become a system, assistant, or tool message because ChatMessage.role accepts arbitrary strings. This can override application instructions, alter the intended prompt structure, or confuse downstream tool and message handling. This issue is fixed in version 2.5.0.
A vulnerability in Banks prior to version 2.5.0 allows user-controlled input to be parsed as privileged chat messages. The issue arises in the `Prompt.chat_messages()` method, which incorrectly processes rendered template data as `ChatMessage` JSON objects. This can lead to injection of system, assistant, or tool messages, disrupting the intended prompt structure and potentially altering application behavior when interfacing with language model providers.
Users can update to Banks version 2.5.0 or later, where this vulnerability is fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Oct 8, 2026CISA-ADP
Assessed Oct 13, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/masci/banks/security/advisories/GHSA-hmq2-7hp6-7crh | CISA-ADP | AdvisoryExploitRemedyVendor |
| https://github.com/masci/banks/commit/02172b816fb84f6a824cc09a8aca7416f53c12cb | [email protected] | Source CodeVendor |
| https://github.com/masci/banks/pull/78 | [email protected] | Source CodeVendor |
| https://github.com/masci/banks/releases/tag/v2.5.0 | [email protected] | Release NotesVendor |
| https://github.com/masci/banks/security/advisories/GHSA-hmq2-7hp6-7crh | [email protected] | AdvisoryExploitRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-20 | Improper Input Validation | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| masci Banks | <= 2.4.5 (semver) |
CPE
Remediation
| |
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Oct 13, 2026 | CVE Modified | CISA-ADP |
| Oct 8, 2026 | New CVE Received | [email protected] |