CVE-2026-107717

Banks: User-controlled prompt input can be parsed as privileged chat messages

MEDIUM
6.5
CVSS Score
Published: October 8, 2026 at 09:38 PM UTC
Updated: October 13, 2026 at 05:17 PM UTC
1 product affected across 1 vendorBanks

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.3%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.5.0

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-20

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